Issue #1916 - Part 1: Convert flags passed to ReflowChild, FinishReflowChild, etc into an enum class.

Backported from Mozilla bug 1571250.

20 files changed, 190 insertions, 148 deletions

diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 152b3d06ad..7f19839a14 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -1182,8 +1182,8 @@ nsBlockFrame::Reflow(nsPresContext*           aPresContext,
   nsOverflowAreas ocBounds;
   nsReflowStatus ocStatus = NS_FRAME_COMPLETE;
   if (GetPrevInFlow()) {
-    ReflowOverflowContainerChildren(aPresContext, *reflowInput, ocBounds, 0,
-                                    ocStatus);
+    ReflowOverflowContainerChildren(aPresContext, *reflowInput, ocBounds,
+                                    ReflowChildFlags::Default, ocStatus);
   }
 
   // Now that we're done cleaning up our overflow container lists, we can
@@ -6297,10 +6297,9 @@ nsBlockFrame::ReflowFloat(BlockReflowInput& aState,
   WritingMode metricsWM = metrics.GetWritingMode();
   aFloat->SetSize(metricsWM, metrics.Size(metricsWM));
   if (aFloat->HasView()) {
-    nsContainerFrame::SyncFrameViewAfterReflow(aState.mPresContext, aFloat,
-                                               aFloat->GetView(),
-                                               metrics.VisualOverflow(),
-                                               NS_FRAME_NO_MOVE_VIEW);
+    nsContainerFrame::SyncFrameViewAfterReflow(
+        aState.mPresContext, aFloat, aFloat->GetView(),
+        metrics.VisualOverflow(), ReflowChildFlags::NoMoveView);
   }
   // Pass floatRS so the frame hierarchy can be used (redoFloatRS has the same hierarchy)
   aFloat->DidReflow(aState.mPresContext, &floatRS,
diff --git a/layout/generic/nsBlockReflowContext.cpp b/layout/generic/nsBlockReflowContext.cpp
index 3be74c929a..494b893917 100644
--- a/layout/generic/nsBlockReflowContext.cpp
+++ b/layout/generic/nsBlockReflowContext.cpp
@@ -456,7 +456,8 @@ nsBlockReflowContext::PlaceBlock(const ReflowInput&  aReflowInput,
   // Now place the frame and complete the reflow process
   nsContainerFrame::FinishReflowChild(mFrame, mPresContext, mMetrics,
                                       &aReflowInput, frameWM, logPos,
-                                      mContainerSize, 0);
+                                      mContainerSize,
+                                      nsIFrame::ReflowChildFlags::Default);
 
   aOverflowAreas = mMetrics.mOverflowAreas + mFrame->GetPosition();
 
diff --git a/layout/generic/nsCanvasFrame.cpp b/layout/generic/nsCanvasFrame.cpp
index 61efb57e25..b4e1f0319a 100644
--- a/layout/generic/nsCanvasFrame.cpp
+++ b/layout/generic/nsCanvasFrame.cpp
@@ -636,12 +636,12 @@ nsCanvasFrame::Reflow(nsPresContext*           aPresContext,
     kidReflowInput.ApplyRelativePositioning(&kidPt, containerSize);
 
     // Reflow the frame
-    ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowInput,
-                kidWM, kidPt, containerSize, 0, aStatus);
+    ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowInput, kidWM,
+                kidPt, containerSize, ReflowChildFlags::Default, aStatus);
 
     // Complete the reflow and position and size the child frame
     FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, &kidReflowInput,
-                      kidWM, kidPt, containerSize, 0);
+                      kidWM, kidPt, containerSize, ReflowChildFlags::Default);
 
     if (!NS_FRAME_IS_FULLY_COMPLETE(aStatus)) {
       nsIFrame* nextFrame = kidFrame->GetNextInFlow();
@@ -696,8 +696,8 @@ nsCanvasFrame::Reflow(nsPresContext*           aPresContext,
 
   if (prevCanvasFrame) {
     ReflowOverflowContainerChildren(aPresContext, aReflowInput,
-                                    aDesiredSize.mOverflowAreas, 0,
-                                    aStatus);
+                                    aDesiredSize.mOverflowAreas,
+                                    ReflowChildFlags::Default, aStatus);
   }
 
   FinishReflowWithAbsoluteFrames(aPresContext, aDesiredSize, aReflowInput, aStatus);
diff --git a/layout/generic/nsColumnSetFrame.cpp b/layout/generic/nsColumnSetFrame.cpp
index 99733c549b..ad4211bd8c 100644
--- a/layout/generic/nsColumnSetFrame.cpp
+++ b/layout/generic/nsColumnSetFrame.cpp
@@ -641,8 +641,8 @@ nsColumnSetFrame::ReflowChildren(ReflowOutput&     aDesiredSize,
                           kidReflowInput.ComputedLogicalMargin().IStart(wm),
                           childOrigin.B(wm) +
                           kidReflowInput.ComputedLogicalMargin().BStart(wm));
-      ReflowChild(child, PresContext(), kidDesiredSize, kidReflowInput,
-                  wm, origin, containerSize, 0, aStatus);
+      ReflowChild(child, PresContext(), kidDesiredSize, kidReflowInput, wm,
+                  origin, containerSize, ReflowChildFlags::Default, aStatus);
 
       reflowNext = (aStatus & NS_FRAME_REFLOW_NEXTINFLOW) != 0;
 
@@ -656,8 +656,9 @@ nsColumnSetFrame::ReflowChildren(ReflowOutput&     aDesiredSize,
 
       *aCarriedOutBEndMargin = kidDesiredSize.mCarriedOutBEndMargin;
 
-      FinishReflowChild(child, PresContext(), kidDesiredSize,
-                        &kidReflowInput, wm, childOrigin, containerSize, 0);
+      FinishReflowChild(child, PresContext(), kidDesiredSize, &kidReflowInput,
+                        wm, childOrigin, containerSize,
+                        ReflowChildFlags::Default);
 
       childContentBEnd = nsLayoutUtils::CalculateContentBEnd(wm, child);
       if (childContentBEnd > aConfig.mColMaxBSize) {
@@ -1052,8 +1053,8 @@ nsColumnSetFrame::Reflow(nsPresContext*           aPresContext,
   nsOverflowAreas ocBounds;
   nsReflowStatus ocStatus = NS_FRAME_COMPLETE;
   if (GetPrevInFlow()) {
-    ReflowOverflowContainerChildren(aPresContext, aReflowInput, ocBounds, 0,
-                                    ocStatus);
+    ReflowOverflowContainerChildren(aPresContext, aReflowInput, ocBounds,
+                                    ReflowChildFlags::Default, ocStatus);
   }
 
   //------------ Handle Incremental Reflow -----------------
diff --git a/layout/generic/nsContainerFrame.cpp b/layout/generic/nsContainerFrame.cpp
index dd20ccffee..21033152b3 100644
--- a/layout/generic/nsContainerFrame.cpp
+++ b/layout/generic/nsContainerFrame.cpp
@@ -755,21 +755,21 @@ void nsContainerFrame::SetSizeConstraints(nsPresContext* aPresContext,
 
 void
 nsContainerFrame::SyncFrameViewAfterReflow(nsPresContext* aPresContext,
-                                           nsIFrame*       aFrame,
+                                           nsIFrame*        aFrame,
                                            nsView*        aView,
-                                           const nsRect&   aVisualOverflowArea,
-                                           uint32_t        aFlags)
+                                           const nsRect&    aVisualOverflowArea,
+                                           ReflowChildFlags aFlags)
 {
   if (!aView) {
     return;
   }
 
   // Make sure the view is sized and positioned correctly
-  if (0 == (aFlags & NS_FRAME_NO_MOVE_VIEW)) {
+  if (!(aFlags & ReflowChildFlags::NoMoveView)) {
     PositionFrameView(aFrame);
   }
 
-  if (0 == (aFlags & NS_FRAME_NO_SIZE_VIEW)) {
+  if (!(aFlags & ReflowChildFlags::NoSizeView)) {
     nsViewManager* vm = aView->GetViewManager();
 
     vm->ResizeView(aView, aVisualOverflowArea, true);
@@ -781,7 +781,7 @@ nsContainerFrame::SyncFrameViewProperties(nsPresContext*  aPresContext,
                                           nsIFrame*        aFrame,
                                           nsStyleContext*  aStyleContext,
                                           nsView*         aView,
-                                          uint32_t         aFlags)
+                                          ReflowChildFlags aFlags)
 {
   NS_ASSERTION(!aStyleContext || aFrame->StyleContext() == aStyleContext,
                "Wrong style context for frame?");
@@ -797,7 +797,7 @@ nsContainerFrame::SyncFrameViewProperties(nsPresContext*  aPresContext,
   }
 
   // Make sure visibility is correct. This only affects nsSubdocumentFrame.
-  if (0 == (aFlags & NS_FRAME_NO_VISIBILITY) &&
+  if (!(aFlags & ReflowChildFlags::NoVisibility) &&
       !aFrame->SupportsVisibilityHidden()) {
     // See if the view should be hidden or visible
     vm->SetViewVisibility(aView,
@@ -1032,7 +1032,7 @@ nsContainerFrame::ReflowChild(nsIFrame*                aKidFrame,
                               const WritingMode&       aWM,
                               const LogicalPoint&      aPos,
                               const nsSize&            aContainerSize,
-                              uint32_t                 aFlags,
+                              ReflowChildFlags         aFlags,
                               nsReflowStatus&          aStatus,
                               nsOverflowContinuationTracker* aTracker)
 {
@@ -1043,11 +1043,12 @@ nsContainerFrame::ReflowChild(nsIFrame*                aKidFrame,
   }
 
   // Position the child frame and its view if requested.
-  if (NS_FRAME_NO_MOVE_FRAME != (aFlags & NS_FRAME_NO_MOVE_FRAME)) {
+  if (ReflowChildFlags::NoMoveFrame !=
+      (aFlags & ReflowChildFlags::NoMoveFrame)) {
     aKidFrame->SetPosition(aWM, aPos, aContainerSize);
   }
 
-  if (0 == (aFlags & NS_FRAME_NO_MOVE_VIEW)) {
+  if (!(aFlags & ReflowChildFlags::NoMoveView)) {
     PositionFrameView(aKidFrame);
     PositionChildViews(aKidFrame);
   }
@@ -1056,10 +1057,9 @@ nsContainerFrame::ReflowChild(nsIFrame*                aKidFrame,
   aKidFrame->Reflow(aPresContext, aDesiredSize, aReflowInput, aStatus);
 
   // If the child frame is complete, delete any next-in-flows,
-  // but only if the NO_DELETE_NEXT_IN_FLOW flag isn't set.
-  if (!NS_INLINE_IS_BREAK_BEFORE(aStatus) &&
-      NS_FRAME_IS_FULLY_COMPLETE(aStatus) &&
-      !(aFlags & NS_FRAME_NO_DELETE_NEXT_IN_FLOW_CHILD)) {
+  // but only if the NoDeleteNextInFlowChild flag isn't set.
+  if (!NS_INLINE_IS_BREAK_BEFORE(aStatus) && NS_FRAME_IS_FULLY_COMPLETE(aStatus) &&
+      !(aFlags & ReflowChildFlags::NoDeleteNextInFlowChild)) {
     nsIFrame* kidNextInFlow = aKidFrame->GetNextInFlow();
     if (kidNextInFlow) {
       // Remove all of the childs next-in-flows. Make sure that we ask
@@ -1080,18 +1080,19 @@ nsContainerFrame::ReflowChild(nsIFrame*                aKidFrame,
                               const ReflowInput& aReflowInput,
                               nscoord                  aX,
                               nscoord                  aY,
-                              uint32_t                 aFlags,
+                              ReflowChildFlags         aFlags,
                               nsReflowStatus&          aStatus,
                               nsOverflowContinuationTracker* aTracker)
 {
   NS_PRECONDITION(aReflowInput.mFrame == aKidFrame, "bad reflow state");
 
   // Position the child frame and its view if requested.
-  if (NS_FRAME_NO_MOVE_FRAME != (aFlags & NS_FRAME_NO_MOVE_FRAME)) {
+  if (ReflowChildFlags::NoMoveFrame !=
+      (aFlags & ReflowChildFlags::NoMoveFrame)) {
     aKidFrame->SetPosition(nsPoint(aX, aY));
   }
 
-  if (0 == (aFlags & NS_FRAME_NO_MOVE_VIEW)) {
+  if (!(aFlags & ReflowChildFlags::NoMoveView)) {
     PositionFrameView(aKidFrame);
     PositionChildViews(aKidFrame);
   }
@@ -1100,9 +1101,9 @@ nsContainerFrame::ReflowChild(nsIFrame*                aKidFrame,
   aKidFrame->Reflow(aPresContext, aDesiredSize, aReflowInput, aStatus);
 
   // If the child frame is complete, delete any next-in-flows,
-  // but only if the NO_DELETE_NEXT_IN_FLOW flag isn't set.
+  // but only if the NoDeleteNextInFlowChild flag isn't set.
   if (NS_FRAME_IS_FULLY_COMPLETE(aStatus) &&
-      !(aFlags & NS_FRAME_NO_DELETE_NEXT_IN_FLOW_CHILD)) {
+      !(aFlags & ReflowChildFlags::NoDeleteNextInFlowChild)) {
     nsIFrame* kidNextInFlow = aKidFrame->GetNextInFlow();
     if (kidNextInFlow) {
       // Remove all of the childs next-in-flows. Make sure that we ask
@@ -1161,11 +1162,11 @@ nsContainerFrame::PositionChildViews(nsIFrame* aFrame)
  * - invoked the DidReflow() function
  *
  * Flags:
- * NS_FRAME_NO_MOVE_FRAME - don't move the frame. aX and aY are ignored in this
- *    case. Also implies NS_FRAME_NO_MOVE_VIEW
- * NS_FRAME_NO_MOVE_VIEW - don't position the frame's view. Set this if you
- *    don't want to automatically sync the frame and view
- * NS_FRAME_NO_SIZE_VIEW - don't size the frame's view
+ * ReflowChildFlags::NoMoveFrame - don't move the frame. aX and aY are ignored
+ *    in this case. Also implies ReflowChildFlags::NoMoveView
+ * ReflowChildFlags::NoMoveView - don't position the frame's view. Set this if
+ *    you don't want to automatically sync the frame and view
+ * ReflowChildFlags::NoSizeView - don't size the frame's view
  */
 void
 nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
@@ -1175,7 +1176,7 @@ nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
                                     const WritingMode&         aWM,
                                     const LogicalPoint&        aPos,
                                     const nsSize&              aContainerSize,
-                                    uint32_t                   aFlags)
+                                    nsIFrame::ReflowChildFlags aFlags)
 {
   if (aWM.IsVerticalRL() || (!aWM.IsVertical() && !aWM.IsBidiLTR())) {
     NS_ASSERTION(aContainerSize.width != NS_UNCONSTRAINEDSIZE,
@@ -1184,10 +1185,11 @@ nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
 
   nsPoint curOrigin = aKidFrame->GetPosition();
   WritingMode outerWM = aDesiredSize.GetWritingMode();
-  LogicalSize convertedSize = aDesiredSize.Size(outerWM).ConvertTo(aWM,
-                                                                   outerWM);
+  LogicalSize convertedSize =
+      aDesiredSize.Size(outerWM).ConvertTo(aWM, outerWM);
 
-  if (NS_FRAME_NO_MOVE_FRAME != (aFlags & NS_FRAME_NO_MOVE_FRAME)) {
+  if (ReflowChildFlags::NoMoveFrame !=
+      (aFlags & ReflowChildFlags::NoMoveFrame)) {
     aKidFrame->SetRect(aWM, LogicalRect(aWM, aPos, convertedSize),
                        aContainerSize);
   } else {
@@ -1203,7 +1205,7 @@ nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
   }
 
   nsPoint newOrigin = aKidFrame->GetPosition();
-  if (!(aFlags & NS_FRAME_NO_MOVE_VIEW) && curOrigin != newOrigin) {
+  if (!(aFlags & ReflowChildFlags::NoMoveView) && curOrigin != newOrigin) {
     if (!aKidFrame->HasView()) {
       // If the frame has moved, then we need to make sure any child views are
       // correctly positioned
@@ -1223,12 +1225,14 @@ nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
                                     const ReflowInput*   aReflowInput,
                                     nscoord                    aX,
                                     nscoord                    aY,
-                                    uint32_t                   aFlags)
+                                    ReflowChildFlags           aFlags)
 {
   nsPoint curOrigin = aKidFrame->GetPosition();
 
-  if (NS_FRAME_NO_MOVE_FRAME != (aFlags & NS_FRAME_NO_MOVE_FRAME)) {
-    aKidFrame->SetRect(nsRect(aX, aY, aDesiredSize.Width(), aDesiredSize.Height()));
+  if (ReflowChildFlags::NoMoveFrame !=
+      (aFlags & ReflowChildFlags::NoMoveFrame)) {
+    aKidFrame->SetRect(
+        nsRect(aX, aY, aDesiredSize.Width(), aDesiredSize.Height()));
   } else {
     aKidFrame->SetSize(nsSize(aDesiredSize.Width(), aDesiredSize.Height()));
   }
@@ -1241,7 +1245,7 @@ nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
                              aDesiredSize.VisualOverflow(), aFlags);
   }
 
-  if (!(aFlags & NS_FRAME_NO_MOVE_VIEW) &&
+  if (!(aFlags & ReflowChildFlags::NoMoveView) &&
       (curOrigin.x != aX || curOrigin.y != aY)) {
     if (!aKidFrame->HasView()) {
       // If the frame has moved, then we need to make sure any child views are
@@ -1253,11 +1257,12 @@ nsContainerFrame::FinishReflowChild(nsIFrame*                  aKidFrame,
   aKidFrame->DidReflow(aPresContext, aReflowInput, nsDidReflowStatus::FINISHED);
 }
 
+
 void
 nsContainerFrame::ReflowOverflowContainerChildren(nsPresContext*           aPresContext,
                                                   const ReflowInput& aReflowInput,
                                                   nsOverflowAreas&         aOverflowRects,
-                                                  uint32_t                 aFlags,
+                                                  ReflowChildFlags         aFlags,
                                                   nsReflowStatus&          aStatus,
                                                   ChildFrameMerger         aMergeFunc)
 {
diff --git a/layout/generic/nsContainerFrame.h b/layout/generic/nsContainerFrame.h
index e3cc54b0b0..030622e8ea 100644
--- a/layout/generic/nsContainerFrame.h
+++ b/layout/generic/nsContainerFrame.h
@@ -13,16 +13,6 @@
 #include "nsFrameList.h"
 #include "nsLayoutUtils.h"
 
-// Option flags for ReflowChild() and FinishReflowChild()
-// member functions
-#define NS_FRAME_NO_MOVE_VIEW         0x0001
-#define NS_FRAME_NO_MOVE_FRAME        (0x0002 | NS_FRAME_NO_MOVE_VIEW)
-#define NS_FRAME_NO_SIZE_VIEW         0x0004
-#define NS_FRAME_NO_VISIBILITY        0x0008
-// Only applies to ReflowChild; if true, don't delete the next-in-flow, even
-// if the reflow is fully complete.
-#define NS_FRAME_NO_DELETE_NEXT_IN_FLOW_CHILD 0x0010
-
 class nsOverflowContinuationTracker;
 
 // Some macros for container classes to do sanity checking on
@@ -173,14 +163,14 @@ public:
   // Set the view's size and position after its frame has been reflowed.
   //
   // Flags:
-  // NS_FRAME_NO_MOVE_VIEW - don't position the frame's view. Set this if you
+  // NoMoveView - don't position the frame's view. Set this if you
   //    don't want to automatically sync the frame and view
-  // NS_FRAME_NO_SIZE_VIEW - don't size the view
-  static void SyncFrameViewAfterReflow(nsPresContext* aPresContext,
-                                       nsIFrame*       aFrame,
-                                       nsView*        aView,
-                                       const nsRect&   aVisualOverflowArea,
-                                       uint32_t        aFlags = 0);
+  // NoSizeView - don't size the view
+  static void SyncFrameViewAfterReflow(nsPresContext*  aPresContext,
+                                       nsIFrame*        aFrame,
+                                       nsView*         aView,
+                                       const nsRect&    aVisualOverflowArea,
+                                       ReflowChildFlags aFlags = ReflowChildFlags::Default);
 
   // Syncs properties to the top level view and window, like transparency and
   // shadow.
@@ -205,7 +195,7 @@ public:
                                       nsIFrame*        aFrame,
                                       nsStyleContext*  aStyleContext,
                                       nsView*         aView,
-                                      uint32_t         aFlags = 0);
+                                      ReflowChildFlags aFlags = ReflowChildFlags::Default);
 
   /**
    * Converts the minimum and maximum sizes given in inner window app units to
@@ -222,7 +212,7 @@ public:
                                  const nsSize& aMaxSize);
 
   // Used by both nsInlineFrame and nsFirstLetterFrame.
-  void DoInlineIntrinsicISize(nsRenderingContext *aRenderingContext,
+  void DoInlineIntrinsicISize(nsRenderingContext* aRenderingContext,
                               InlineIntrinsicISizeData *aData,
                               nsLayoutUtils::IntrinsicISizeType aType);
 
@@ -248,10 +238,10 @@ public:
    * @param aContainerSize  size of the border-box of the containing frame
    *
    * Flags:
-   * NS_FRAME_NO_MOVE_VIEW - don't position the frame's view. Set this if you
+   * NoMoveView - don't position the frame's view. Set this if you
    *    don't want to automatically sync the frame and view
-   * NS_FRAME_NO_MOVE_FRAME - don't move the frame. aPos is ignored in this
-   *    case. Also implies NS_FRAME_NO_MOVE_VIEW
+   * NoMoveFrame - don't move the frame. aPos is ignored in this
+   *    case. Also implies NoMoveView
    */
   void ReflowChild(nsIFrame*                      aChildFrame,
                    nsPresContext*                 aPresContext,
@@ -260,7 +250,7 @@ public:
                    const mozilla::WritingMode&    aWM,
                    const mozilla::LogicalPoint&   aPos,
                    const nsSize&                  aContainerSize,
-                   uint32_t                       aFlags,
+                   ReflowChildFlags               aFlags,
                    nsReflowStatus&                aStatus,
                    nsOverflowContinuationTracker* aTracker = nullptr);
 
@@ -277,11 +267,11 @@ public:
    * @param aContainerSize  size of the border-box of the containing frame
    *
    * Flags:
-   * NS_FRAME_NO_MOVE_FRAME - don't move the frame. aPos is ignored in this
-   *    case. Also implies NS_FRAME_NO_MOVE_VIEW
-   * NS_FRAME_NO_MOVE_VIEW - don't position the frame's view. Set this if you
+   * NoMoveFrame - don't move the frame. aPos is ignored in this
+   *    case. Also implies NoMoveView
+   * NoMoveView - don't position the frame's view. Set this if you
    *    don't want to automatically sync the frame and view
-   * NS_FRAME_NO_SIZE_VIEW - don't size the frame's view
+   * NoSizeView - don't size the frame's view
    */
   static void FinishReflowChild(nsIFrame*                    aKidFrame,
                                 nsPresContext*               aPresContext,
@@ -290,7 +280,8 @@ public:
                                 const mozilla::WritingMode&  aWM,
                                 const mozilla::LogicalPoint& aPos,
                                 const nsSize&                aContainerSize,
-                                uint32_t                     aFlags);
+                                ReflowChildFlags             aFlags);
+
 
   //XXX temporary: hold on to a copy of the old physical versions of
   //    ReflowChild and FinishReflowChild so that we can convert callers
@@ -301,7 +292,7 @@ public:
                    const ReflowInput&       aReflowInput,
                    nscoord                        aX,
                    nscoord                        aY,
-                   uint32_t                       aFlags,
+                   ReflowChildFlags               aFlags,
                    nsReflowStatus&                aStatus,
                    nsOverflowContinuationTracker* aTracker = nullptr);
 
@@ -311,7 +302,8 @@ public:
                                 const ReflowInput*   aReflowInput,
                                 nscoord                    aX,
                                 nscoord                    aY,
-                                uint32_t                   aFlags);
+                                ReflowChildFlags           aFlags);
+
 
   static void PositionChildViews(nsIFrame* aFrame);
 
@@ -391,11 +383,12 @@ public:
   void ReflowOverflowContainerChildren(nsPresContext*           aPresContext,
                                        const ReflowInput& aReflowInput,
                                        nsOverflowAreas&         aOverflowRects,
-                                       uint32_t                 aFlags,
+                                       ReflowChildFlags         aFlags,
                                        nsReflowStatus&          aStatus,
                                        ChildFrameMerger aMergeFunc =
                                          DefaultChildFrameMerge);
 
+
   /**
    * Move any frames on our overflow list to the end of our principal list.
    * @return true if there were any overflow frames
diff --git a/layout/generic/nsFlexContainerFrame.cpp b/layout/generic/nsFlexContainerFrame.cpp
index 4429111e46..18a0643f14 100644
--- a/layout/generic/nsFlexContainerFrame.cpp
+++ b/layout/generic/nsFlexContainerFrame.cpp
@@ -1856,7 +1856,7 @@ nsFlexContainerFrame::MeasureAscentAndHeightForFlexItem(
   ReflowOutput childDesiredSize(aChildReflowInput);
   nsReflowStatus childReflowStatus;
 
-  const uint32_t flags = NS_FRAME_NO_MOVE_FRAME;
+  const ReflowChildFlags flags = ReflowChildFlags::NoMoveFrame;
   ReflowChild(aItem.Frame(), aPresContext,
               childDesiredSize, aChildReflowInput,
               0, 0, flags, childReflowStatus);
@@ -4856,7 +4856,8 @@ nsFlexContainerFrame::ReflowFlexItem(nsPresContext* aPresContext,
   ReflowChild(aItem.Frame(), aPresContext,
               childDesiredSize, childReflowInput,
               outerWM, aFramePos, aContainerSize,
-              0, childReflowStatus);
+              ReflowChildFlags::Default,
+              childReflowStatus);
 
   // XXXdholbert Once we do pagination / splitting, we'll need to actually
   // handle incomplete childReflowStatuses. But for now, we give our kids
@@ -4872,9 +4873,9 @@ nsFlexContainerFrame::ReflowFlexItem(nsPresContext* aPresContext,
                                               offsets, &aFramePos,
                                               aContainerSize);
 
-  FinishReflowChild(aItem.Frame(), aPresContext,
-                    childDesiredSize, &childReflowInput,
-                    outerWM, aFramePos, aContainerSize, 0);
+  FinishReflowChild(aItem.Frame(), aPresContext, childDesiredSize,
+                    &childReflowInput, outerWM, aFramePos, aContainerSize,
+                    ReflowChildFlags::Default);
 
   aItem.SetAscent(childDesiredSize.BlockStartAscent());
 }
@@ -4899,14 +4900,13 @@ nsFlexContainerFrame::ReflowPlaceholders(nsPresContext* aPresContext,
                                  placeholder, availSize);
     ReflowOutput childDesiredSize(childReflowInput);
     nsReflowStatus childReflowStatus;
-    ReflowChild(placeholder, aPresContext,
-                childDesiredSize, childReflowInput,
-                outerWM, aContentBoxOrigin, aContainerSize, 0,
-                childReflowStatus);
-
-    FinishReflowChild(placeholder, aPresContext,
-                      childDesiredSize, &childReflowInput,
-                      outerWM, aContentBoxOrigin, aContainerSize, 0);
+    ReflowChild(placeholder, aPresContext, childDesiredSize, childReflowInput,
+                outerWM, aContentBoxOrigin, aContainerSize,
+                ReflowChildFlags::Default, childReflowStatus);
+
+    FinishReflowChild(placeholder, aPresContext, childDesiredSize,
+                      &childReflowInput, outerWM, aContentBoxOrigin,
+                      aContainerSize, ReflowChildFlags::Default);
 
     // Mark the placeholder frame to indicate that it's not actually at the
     // element's static position, because we need to apply CSS Alignment after
diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index 7e819ddf3b..43ad970890 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -6583,9 +6583,9 @@ nsIFrame::UpdateOverflow()
   if (FinishAndStoreOverflow(overflowAreas, GetSize())) {
     nsView* view = GetView();
     if (view) {
-      uint32_t flags = GetXULLayoutFlags();
+      ReflowChildFlags flags = GetXULLayoutFlags();
 
-      if ((flags & NS_FRAME_NO_SIZE_VIEW) == 0) {
+      if (!(flags & ReflowChildFlags::NoSizeView)) {
         // Make sure the frame's view is properly sized.
         nsViewManager* vm = view->GetViewManager();
         vm->ResizeView(view, overflowAreas.VisualOverflow(), true);
@@ -9820,9 +9820,10 @@ nsFrame::BoxReflow(nsBoxLayoutState&        aState,
 
     NS_ASSERTION(NS_FRAME_IS_COMPLETE(status), "bad status");
 
-    uint32_t layoutFlags = aState.LayoutFlags();
+    ReflowChildFlags layoutFlags = aState.LayoutFlags();
     nsContainerFrame::FinishReflowChild(this, aPresContext, aDesiredSize,
-                                        &reflowInput, aX, aY, layoutFlags | NS_FRAME_NO_MOVE_FRAME);
+                                        &reflowInput, aX, aY, layoutFlags |
+                                        ReflowChildFlags::NoMoveFrame);
 
     // Save the ascent.  (bug 103925)
     if (IsXULCollapsed()) {
diff --git a/layout/generic/nsFrameSetFrame.cpp b/layout/generic/nsFrameSetFrame.cpp
index 4315b9b8af..a3970b5a98 100644
--- a/layout/generic/nsFrameSetFrame.cpp
+++ b/layout/generic/nsFrameSetFrame.cpp
@@ -699,13 +699,14 @@ nsHTMLFramesetFrame::ReflowPlaceChild(nsIFrame*                aChild,
   nsReflowStatus status;
 
   ReflowChild(aChild, aPresContext, reflowOutput, reflowInput, aOffset.x,
-              aOffset.y, 0, status);
+              aOffset.y, ReflowChildFlags::Default, status);
   NS_ASSERTION(NS_FRAME_IS_COMPLETE(status), "bad status");
 
   // Place and size the child
   reflowOutput.Width() = aSize.width;
   reflowOutput.Height() = aSize.height;
-  FinishReflowChild(aChild, aPresContext, reflowOutput, nullptr, aOffset.x, aOffset.y, 0);
+  FinishReflowChild(aChild, aPresContext, reflowOutput, nullptr, aOffset.x,
+                    aOffset.y, ReflowChildFlags::Default);
 }
 
 static
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index bbde1d7dc0..ff8500b92f 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -571,11 +571,11 @@ nsHTMLScrollFrame::ReflowScrolledFrame(ScrollReflowInput* aState,
   nsReflowStatus status;
   // No need to pass a true container-size to ReflowChild or
   // FinishReflowChild, because it's only used there when positioning
-  // the frame (i.e. if NS_FRAME_NO_MOVE_FRAME isn't set)
+  // the frame (i.e. if ReflowChildFlags::NoMoveFrame isn't set)
   const nsSize dummyContainerSize;
-  ReflowChild(mHelper.mScrolledFrame, presContext, *aMetrics,
-              kidReflowInput, wm, LogicalPoint(wm), dummyContainerSize,
-              NS_FRAME_NO_MOVE_FRAME, status);
+  ReflowChild(mHelper.mScrolledFrame, presContext, *aMetrics, kidReflowInput,
+              wm, LogicalPoint(wm), dummyContainerSize,
+              ReflowChildFlags::NoMoveFrame, status);
 
   mHelper.mHasHorizontalScrollbar = didHaveHorizontalScrollbar;
   mHelper.mHasVerticalScrollbar = didHaveVerticalScrollbar;
@@ -588,7 +588,7 @@ nsHTMLScrollFrame::ReflowScrolledFrame(ScrollReflowInput* aState,
   FinishReflowChild(mHelper.mScrolledFrame, presContext,
                     *aMetrics, &kidReflowInput, wm, LogicalPoint(wm),
                     dummyContainerSize,
-                    NS_FRAME_NO_MOVE_FRAME | NS_FRAME_NO_SIZE_VIEW);
+                    ReflowChildFlags::NoMoveFrame | ReflowChildFlags::NoSizeView);
 
   // XXX Some frames (e.g., nsPluginFrame, nsFrameFrame, nsTextFrame) don't bother
   // setting their mOverflowArea. This is wrong because every frame should
@@ -801,7 +801,7 @@ nsHTMLScrollFrame::PlaceScrollArea(ScrollReflowInput& aState,
                                              scrolledFrame,
                                              scrolledFrame->GetView(),
                                              scrolledArea,
-                                             0);
+                                             ReflowChildFlags::Default);
 }
 
 nscoord
@@ -1664,7 +1664,7 @@ nsXULScrollFrame::GetFrameName(nsAString& aResult) const
 NS_IMETHODIMP
 nsXULScrollFrame::DoXULLayout(nsBoxLayoutState& aState)
 {
-  uint32_t flags = aState.LayoutFlags();
+  ReflowChildFlags flags = aState.LayoutFlags();
   nsresult rv = XULLayout(aState);
   aState.SetLayoutFlags(flags);
 
@@ -4956,14 +4956,12 @@ nsXULScrollFrame::AddRemoveScrollbar(bool& aHasScrollbar, nscoord& aXY,
    return false;
 }
 
-void
-nsXULScrollFrame::LayoutScrollArea(nsBoxLayoutState& aState,
-                                   const nsPoint& aScrollPosition)
-{
-  uint32_t oldflags = aState.LayoutFlags();
+void nsXULScrollFrame::LayoutScrollArea(nsBoxLayoutState& aState,
+                                        const nsPoint& aScrollPosition) {
+  ReflowChildFlags oldflags = aState.LayoutFlags();
   nsRect childRect = nsRect(mHelper.mScrollPort.TopLeft() - aScrollPosition,
                             mHelper.mScrollPort.Size());
-  int32_t flags = NS_FRAME_NO_MOVE_VIEW;
+  ReflowChildFlags flags = ReflowChildFlags::NoMoveView;
 
   nsSize minSize = mHelper.mScrolledFrame->GetXULMinSize(aState);
 
diff --git a/layout/generic/nsGridContainerFrame.cpp b/layout/generic/nsGridContainerFrame.cpp
index 0a953d6fff..34113e4fa7 100644
--- a/layout/generic/nsGridContainerFrame.cpp
+++ b/layout/generic/nsGridContainerFrame.cpp
@@ -3789,7 +3789,10 @@ MeasuringReflow(nsIFrame*           aChild,
   ReflowInput childRI(pc, *rs, aChild, aAvailableSize, &aCBSize, riFlags);
   ReflowOutput childSize(childRI);
   nsReflowStatus childStatus;
-  const uint32_t flags = NS_FRAME_NO_MOVE_FRAME | NS_FRAME_NO_SIZE_VIEW;
+  const nsIFrame::ReflowChildFlags flags =
+      nsIFrame::ReflowChildFlags::NoMoveFrame |
+      nsIFrame::ReflowChildFlags::NoSizeView |
+      nsIFrame::ReflowChildFlags::NoDeleteNextInFlowChild;
   parent->ReflowChild(aChild, pc, childSize, childRI, wm,
                       LogicalPoint(wm), nsSize(), flags, childStatus);
   parent->FinishReflowChild(aChild, pc, childSize, &childRI, wm,
@@ -5341,7 +5344,7 @@ nsGridContainerFrame::ReflowInFlowChild(nsIFrame*              aChild,
   ReflowOutput childSize(childRI);
   const nsSize dummyContainerSize;
   ReflowChild(aChild, pc, childSize, childRI, childWM, LogicalPoint(childWM),
-              dummyContainerSize, 0, aStatus);
+              dummyContainerSize, ReflowChildFlags::Default, aStatus);
   LogicalPoint childPos =
     cb.Origin(wm).ConvertTo(childWM, wm,
                             aContainerSize - childSize.PhysicalSize());
@@ -5370,7 +5373,7 @@ nsGridContainerFrame::ReflowInFlowChild(nsIFrame*              aChild,
 
   childRI.ApplyRelativePositioning(&childPos, aContainerSize);
   FinishReflowChild(aChild, pc, childSize, &childRI, childWM, childPos,
-                    aContainerSize, 0);
+                    aContainerSize, ReflowChildFlags::Default);
   ConsiderChildOverflow(aDesiredSize.mOverflowAreas, aChild);
 }
 
@@ -5884,14 +5887,15 @@ nsGridContainerFrame::ReflowChildren(GridReflowInput&     aState,
                                      nsReflowStatus&      aStatus)
 {
   MOZ_ASSERT(aState.mReflowInput);
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
 
   aStatus = NS_FRAME_COMPLETE;
   nsOverflowAreas ocBounds;
   nsReflowStatus ocStatus = NS_FRAME_COMPLETE;
   if (GetPrevInFlow()) {
     ReflowOverflowContainerChildren(PresContext(), *aState.mReflowInput,
-                                    ocBounds, 0, ocStatus,
-                                    MergeSortedFrameListsFor);
+                                    ocBounds, ReflowChildFlags::Default,
+                                    ocStatus, MergeSortedFrameListsFor);
   }
 
   WritingMode wm = aState.mReflowInput->GetWritingMode();
diff --git a/layout/generic/nsHTMLCanvasFrame.cpp b/layout/generic/nsHTMLCanvasFrame.cpp
index f40f799bab..8808907006 100644
--- a/layout/generic/nsHTMLCanvasFrame.cpp
+++ b/layout/generic/nsHTMLCanvasFrame.cpp
@@ -281,10 +281,10 @@ nsHTMLCanvasFrame::Reflow(nsPresContext*           aPresContext,
   ReflowOutput childDesiredSize(aReflowInput.GetWritingMode(), aMetrics.mFlags);
   ReflowInput childReflowInput(aPresContext, aReflowInput, childFrame,
                                      availSize);
-  ReflowChild(childFrame, aPresContext, childDesiredSize, childReflowInput,
-              0, 0, 0, childStatus, nullptr);
+  ReflowChild(childFrame, aPresContext, childDesiredSize, childReflowInput, 0,
+              0, ReflowChildFlags::Default, childStatus, nullptr);
   FinishReflowChild(childFrame, aPresContext, childDesiredSize,
-                    &childReflowInput, 0, 0, 0);
+                    &childReflowInput, 0, 0, ReflowChildFlags::Default);
 
   NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                   ("exit nsHTMLCanvasFrame::Reflow: size=%d,%d",
diff --git a/layout/generic/nsIFrame.h b/layout/generic/nsIFrame.h
index bc5a5fe971..89557a1e35 100644
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -2239,6 +2239,19 @@ public:
                       const ReflowInput& aReflowInput,
                       nsReflowStatus&          aStatus) = 0;
 
+  // Option flags for ReflowChild() and FinishReflowChild()
+  // member functions
+  enum class ReflowChildFlags : uint32_t {
+    Default = 0,
+    NoMoveView = 1 << 0,
+    NoMoveFrame = (1 << 1) | NoMoveView,
+    NoSizeView = 1 << 2,
+    NoVisibility = 1 << 3,
+    // Only applies to ReflowChild; if true, don't delete the next-in-flow, even
+    // if the reflow is fully complete.
+    NoDeleteNextInFlowChild = 1 << 4
+  };
+
   /**
    * Post-reflow hook. After a frame is reflowed this method will be called
    * informing the frame that this reflow process is complete, and telling the
@@ -3213,8 +3226,9 @@ size_t SizeOfFramePropertiesForTree(mozilla::MallocSizeOf aMallocSizeOf) const;
   virtual nsBoxLayout* GetXULLayoutManager() { return nullptr; }
   nsresult GetXULClientRect(nsRect& aContentRect);
 
-  virtual uint32_t GetXULLayoutFlags()
-  { return 0; }
+  virtual ReflowChildFlags GetXULLayoutFlags() {
+    return ReflowChildFlags::Default;
+  }
 
   // For nsSprocketLayout
   virtual Valignment GetXULVAlign() const = 0;
@@ -3776,6 +3790,8 @@ public:
 #endif
 };
 
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(nsIFrame::ReflowChildFlags)
+
 //----------------------------------------------------------------------
 
 /**
diff --git a/layout/generic/nsLineLayout.cpp b/layout/generic/nsLineLayout.cpp
index 60e4e8c964..8cac02d603 100644
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -3331,7 +3331,7 @@ nsLineLayout::RelativePositionFrames(PerSpanData* psd, nsOverflowAreas& aOverflo
     if (frame->HasView())
       nsContainerFrame::SyncFrameViewAfterReflow(mPresContext, frame,
         frame->GetView(), pfd->mOverflowAreas.VisualOverflow(),
-        NS_FRAME_NO_SIZE_VIEW);
+        nsIFrame::ReflowChildFlags::NoSizeView);
 
     // Note: the combined area of a child is in its coordinate
     // system. We adjust the childs combined area into our coordinate
@@ -3379,7 +3379,7 @@ nsLineLayout::RelativePositionFrames(PerSpanData* psd, nsOverflowAreas& aOverflo
       nsContainerFrame::SyncFrameViewAfterReflow(mPresContext, frame,
                                                  frame->GetView(),
                                                  r.VisualOverflow(),
-                                                 NS_FRAME_NO_MOVE_VIEW);
+                                                 nsIFrame::ReflowChildFlags::NoMoveView);
 
     overflowAreas.UnionWith(r + frame->GetPosition());
   }
diff --git a/layout/generic/nsPageContentFrame.cpp b/layout/generic/nsPageContentFrame.cpp
index 2c7348afca..cb558374db 100644
--- a/layout/generic/nsPageContentFrame.cpp
+++ b/layout/generic/nsPageContentFrame.cpp
@@ -58,12 +58,13 @@ nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
     kidReflowInput.SetComputedBSize(logicalSize.BSize(wm));
 
     // Reflow the page content area
-    ReflowChild(frame, aPresContext, aDesiredSize, kidReflowInput, 0, 0, 0, aStatus);
+    ReflowChild(frame, aPresContext, aDesiredSize, kidReflowInput, 0, 0,
+                ReflowChildFlags::Default, aStatus);
 
     // The document element's background should cover the entire canvas, so
     // take into account the combined area and any space taken up by
     // absolutely positioned elements
-    nsMargin padding(0,0,0,0);
+    nsMargin padding(0, 0, 0, 0);
 
     // XXXbz this screws up percentage padding (sets padding to zero
     // in the percentage padding case)
@@ -87,10 +88,12 @@ nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
     }
 
     // Place and size the child
-    FinishReflowChild(frame, aPresContext, aDesiredSize, &kidReflowInput, 0, 0, 0);
+    FinishReflowChild(frame, aPresContext, aDesiredSize, &kidReflowInput, 0, 0,
+                      ReflowChildFlags::Default);
 
-    NS_ASSERTION(aPresContext->IsDynamic() || !NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
-                  !frame->GetNextInFlow(), "bad child flow list");
+    NS_ASSERTION(aPresContext->IsDynamic() || !aStatus.IsFullyComplete() ||
+                     !frame->GetNextInFlow(),
+                 "bad child flow list");
   }
 
   // Reflow our fixed frames
diff --git a/layout/generic/nsPageFrame.cpp b/layout/generic/nsPageFrame.cpp
index 31a686e83e..6120e35103 100644
--- a/layout/generic/nsPageFrame.cpp
+++ b/layout/generic/nsPageFrame.cpp
@@ -141,13 +141,15 @@ nsPageFrame::Reflow(nsPresContext*           aPresContext,
     nscoord yc = mPageContentMargin.top;
 
     // Get the child's desired size
-    ReflowChild(frame, aPresContext, aDesiredSize, kidReflowInput, xc, yc, 0, aStatus);
+    ReflowChild(frame, aPresContext, aDesiredSize, kidReflowInput, xc, yc,
+                ReflowChildFlags::Default, aStatus);
 
     // Place and size the child
-    FinishReflowChild(frame, aPresContext, aDesiredSize, &kidReflowInput, xc, yc, 0);
+    FinishReflowChild(frame, aPresContext, aDesiredSize, &kidReflowInput, xc,
+                      yc, ReflowChildFlags::Default);
 
-    NS_ASSERTION(!NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
-                 !frame->GetNextInFlow(), "bad child flow list");
+    NS_ASSERTION(!aStatus.IsFullyComplete() || !frame->GetNextInFlow(),
+                 "bad child flow list");
   }
   PR_PL(("PageFrame::Reflow %p ", this));
   PR_PL(("[%d,%d][%d,%d]\n", aDesiredSize.Width(), aDesiredSize.Height(),
diff --git a/layout/generic/nsRubyFrame.cpp b/layout/generic/nsRubyFrame.cpp
index 797b00fcf1..b6a3d0180d 100644
--- a/layout/generic/nsRubyFrame.cpp
+++ b/layout/generic/nsRubyFrame.cpp
@@ -345,7 +345,8 @@ nsRubyFrame::ReflowSegment(nsPresContext* aPresContext,
     // correct. We will fix it in nsLineLayout after the whole line is
     // reflowed.
     FinishReflowChild(textContainer, aPresContext, textMetrics,
-                      &textReflowInput, lineWM, position, dummyContainerSize, 0);
+                      &textReflowInput, lineWM, position, dummyContainerSize,
+                      ReflowChildFlags::Default);
   }
   MOZ_ASSERT(baseRect.ISize(lineWM) == offsetRect.ISize(lineWM),
              "Annotations should only be placed on the block directions");
diff --git a/layout/generic/nsSimplePageSequenceFrame.cpp b/layout/generic/nsSimplePageSequenceFrame.cpp
index d8ec898a6a..444512fba6 100644
--- a/layout/generic/nsSimplePageSequenceFrame.cpp
+++ b/layout/generic/nsSimplePageSequenceFrame.cpp
@@ -255,13 +255,15 @@ nsSimplePageSequenceFrame::Reflow(nsPresContext*          aPresContext,
     nscoord x = pageCSSMargin.left;
 
     // Place and size the page.
-    ReflowChild(kidFrame, aPresContext, kidSize, kidReflowInput, x, y, 0, status);
+    ReflowChild(kidFrame, aPresContext, kidSize, kidReflowInput, x, y,
+                ReflowChildFlags::Default, status);
 
     // If the page is narrower than our width, then center it horizontally:
     x += ComputeCenteringMargin(aReflowInput.ComputedWidth(),
                                 kidSize.Width(), pageCSSMargin);
 
-    FinishReflowChild(kidFrame, aPresContext, kidSize, nullptr, x, y, 0);
+    FinishReflowChild(kidFrame, aPresContext, kidSize, nullptr, x, y,
+                      ReflowChildFlags::Default);
     y += kidSize.Height();
     y += pageCSSMargin.bottom;
 
diff --git a/layout/generic/nsVideoFrame.cpp b/layout/generic/nsVideoFrame.cpp
index 0472ebe626..7986f672c1 100644
--- a/layout/generic/nsVideoFrame.cpp
+++ b/layout/generic/nsVideoFrame.cpp
@@ -308,6 +308,9 @@ nsVideoFrame::Reflow(nsPresContext* aPresContext,
   // Reflow the child frames. We may have up to two, an image frame
   // which is the poster, and a box frame, which is the video controls.
   for (nsIFrame* child : mFrames) {
+    nsSize oldChildSize = child->GetSize();
+    nsReflowStatus childStatus;
+
     if (child->GetContent() == mPosterImage) {
       // Reflow the poster frame.
       nsImageFrame* imageFrame = static_cast<nsImageFrame*>(child);
@@ -332,10 +335,15 @@ nsVideoFrame::Reflow(nsPresContext* aPresContext,
       kidReflowInput.SetComputedWidth(posterRenderRect.width);
       kidReflowInput.SetComputedHeight(posterRenderRect.height);
       ReflowChild(imageFrame, aPresContext, kidDesiredSize, kidReflowInput,
-                  posterRenderRect.x, posterRenderRect.y, 0, aStatus);
-      FinishReflowChild(imageFrame, aPresContext,
-                        kidDesiredSize, &kidReflowInput,
-                        posterRenderRect.x, posterRenderRect.y, 0);
+                  posterRenderRect.x, posterRenderRect.y,
+                  ReflowChildFlags::Default, childStatus);
+      MOZ_ASSERT(childStatus.IsFullyComplete(),
+                 "We gave our child unconstrained available block-size, "
+                 "so it should be complete!");
+
+      FinishReflowChild(imageFrame, aPresContext, kidDesiredSize,
+                        &kidReflowInput, posterRenderRect.x, posterRenderRect.y,
+                        ReflowChildFlags::Default);
     } else if (child->GetContent() == mVideoControls) {
       // Reflow the video controls frame.
       nsBoxLayoutState boxState(PresContext(), aReflowInput.mRenderingContext);
@@ -370,10 +378,16 @@ nsVideoFrame::Reflow(nsPresContext* aPresContext,
       kidReflowInput.SetComputedHeight(std::max(size.height, 0));
 
       ReflowChild(child, aPresContext, kidDesiredSize, kidReflowInput,
-                  mBorderPadding.left, mBorderPadding.top, 0, aStatus);
+                  mBorderPadding.left, mBorderPadding.top,
+                  ReflowChildFlags::Default, childStatus);
+      MOZ_ASSERT(childStatus.IsFullyComplete(),
+                 "We gave our child unconstrained available block-size, "
+                 "so it should be complete!");
+
       FinishReflowChild(child, aPresContext,
                         kidDesiredSize, &kidReflowInput,
-                        mBorderPadding.left, mBorderPadding.top, 0);
+                        mBorderPadding.left, mBorderPadding.top,
+                        ReflowChildFlags::Default);
     }
   }
   aMetrics.SetOverflowAreasToDesiredBounds();
diff --git a/layout/generic/nsViewportFrame.cpp b/layout/generic/nsViewportFrame.cpp
index a37d2a5a7c..ec933b84e3 100644
--- a/layout/generic/nsViewportFrame.cpp
+++ b/layout/generic/nsViewportFrame.cpp
@@ -315,11 +315,12 @@ ViewportFrame::Reflow(nsPresContext*           aPresContext,
 
       // Reflow the frame
       kidReflowInput.SetComputedBSize(aReflowInput.ComputedBSize());
-      ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowInput,
-                  0, 0, 0, aStatus);
+      ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowInput, 0, 0,
+                  ReflowChildFlags::Default, aStatus);
       kidBSize = kidDesiredSize.BSize(wm);
 
-      FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, nullptr, 0, 0, 0);
+      FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, nullptr, 0, 0,
+                  ReflowChildFlags::Default);
     } else {
       kidBSize = LogicalSize(wm, mFrames.FirstChild()->GetSize()).BSize(wm);
     }