Add m-esr52 at 52.6.0

1 files changed, 828 insertions, 0 deletions

diff --git a/widget/nsBaseDragService.cpp b/widget/nsBaseDragService.cpp
new file mode 100644
index 0000000000..10d3163b33
--- /dev/null
+++ b/widget/nsBaseDragService.cpp
@@ -0,0 +1,828 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsBaseDragService.h"
+#include "nsITransferable.h"
+
+#include "nsIServiceManager.h"
+#include "nsITransferable.h"
+#include "nsSize.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+#include "nsCOMPtr.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIFrame.h"
+#include "nsIDocument.h"
+#include "nsIContent.h"
+#include "nsIPresShell.h"
+#include "nsViewManager.h"
+#include "nsIDOMNode.h"
+#include "nsIDOMDragEvent.h"
+#include "nsISelection.h"
+#include "nsISelectionPrivate.h"
+#include "nsPresContext.h"
+#include "nsIDOMDataTransfer.h"
+#include "nsIImageLoadingContent.h"
+#include "imgIContainer.h"
+#include "imgIRequest.h"
+#include "ImageRegion.h"
+#include "nsRegion.h"
+#include "nsXULPopupManager.h"
+#include "nsMenuPopupFrame.h"
+#include "SVGImageContext.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/DataTransferItemList.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/Unused.h"
+#include "nsFrameLoader.h"
+#include "TabParent.h"
+
+#include "gfxContext.h"
+#include "gfxPlatform.h"
+#include <algorithm>
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+using namespace mozilla::image;
+
+#define DRAGIMAGES_PREF "nglayout.enable_drag_images"
+
+nsBaseDragService::nsBaseDragService()
+  : mCanDrop(false), mOnlyChromeDrop(false), mDoingDrag(false),
+    mHasImage(false), mUserCancelled(false),
+    mDragEventDispatchedToChildProcess(false),
+    mDragAction(DRAGDROP_ACTION_NONE),
+    mDragActionFromChildProcess(DRAGDROP_ACTION_UNINITIALIZED), mTargetSize(0,0),
+    mContentPolicyType(nsIContentPolicy::TYPE_OTHER),
+    mSuppressLevel(0), mInputSource(nsIDOMMouseEvent::MOZ_SOURCE_MOUSE)
+{
+}
+
+nsBaseDragService::~nsBaseDragService()
+{
+}
+
+NS_IMPL_ISUPPORTS(nsBaseDragService, nsIDragService, nsIDragSession)
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetCanDrop(bool aCanDrop)
+{
+  mCanDrop = aCanDrop;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetCanDrop(bool * aCanDrop)
+{
+  *aCanDrop = mCanDrop;
+  return NS_OK;
+}
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetOnlyChromeDrop(bool aOnlyChrome)
+{
+  mOnlyChromeDrop = aOnlyChrome;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetOnlyChromeDrop(bool* aOnlyChrome)
+{
+  *aOnlyChrome = mOnlyChromeDrop;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetDragAction(uint32_t anAction)
+{
+  mDragAction = anAction;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetDragAction(uint32_t * anAction)
+{
+  *anAction = mDragAction;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetTargetSize(nsSize aDragTargetSize)
+{
+  mTargetSize = aDragTargetSize;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetTargetSize(nsSize * aDragTargetSize)
+{
+  *aDragTargetSize = mTargetSize;
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+
+NS_IMETHODIMP
+nsBaseDragService::GetNumDropItems(uint32_t * aNumItems)
+{
+  *aNumItems = 0;
+  return NS_ERROR_FAILURE;
+}
+
+
+//
+// GetSourceDocument
+//
+// Returns the DOM document where the drag was initiated. This will be
+// nullptr if the drag began outside of our application.
+//
+NS_IMETHODIMP
+nsBaseDragService::GetSourceDocument(nsIDOMDocument** aSourceDocument)
+{
+  *aSourceDocument = mSourceDocument.get();
+  NS_IF_ADDREF(*aSourceDocument);
+
+  return NS_OK;
+}
+
+//
+// GetSourceNode
+//
+// Returns the DOM node where the drag was initiated. This will be
+// nullptr if the drag began outside of our application.
+//
+NS_IMETHODIMP
+nsBaseDragService::GetSourceNode(nsIDOMNode** aSourceNode)
+{
+  *aSourceNode = mSourceNode.get();
+  NS_IF_ADDREF(*aSourceNode);
+
+  return NS_OK;
+}
+
+
+//-------------------------------------------------------------------------
+
+NS_IMETHODIMP
+nsBaseDragService::GetData(nsITransferable * aTransferable,
+                           uint32_t aItemIndex)
+{
+  return NS_ERROR_FAILURE;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::IsDataFlavorSupported(const char *aDataFlavor,
+                                         bool *_retval)
+{
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::GetDataTransfer(nsIDOMDataTransfer** aDataTransfer)
+{
+  *aDataTransfer = mDataTransfer;
+  NS_IF_ADDREF(*aDataTransfer);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetDataTransfer(nsIDOMDataTransfer* aDataTransfer)
+{
+  mDataTransfer = aDataTransfer;
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSession(nsIDOMNode *aDOMNode,
+                                     nsIArray* aTransferableArray,
+                                     nsIScriptableRegion* aDragRgn,
+                                     uint32_t aActionType,
+                                     nsContentPolicyType aContentPolicyType =
+                                       nsIContentPolicy::TYPE_OTHER)
+{
+  PROFILER_LABEL_FUNC(js::ProfileEntry::Category::OTHER);
+
+  NS_ENSURE_TRUE(aDOMNode, NS_ERROR_INVALID_ARG);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  // stash the document of the dom node
+  aDOMNode->GetOwnerDocument(getter_AddRefs(mSourceDocument));
+  mSourceNode = aDOMNode;
+  mContentPolicyType = aContentPolicyType;
+  mEndDragPoint = LayoutDeviceIntPoint(0, 0);
+
+  // When the mouse goes down, the selection code starts a mouse
+  // capture. However, this gets in the way of determining drag
+  // feedback for things like trees because the event coordinates
+  // are in the wrong coord system, so turn off mouse capture.
+  nsIPresShell::ClearMouseCapture(nullptr);
+
+  nsresult rv = InvokeDragSessionImpl(aTransferableArray,
+                                      aDragRgn, aActionType);
+
+  if (NS_FAILED(rv)) {
+    mSourceNode = nullptr;
+    mSourceDocument = nullptr;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSessionWithImage(nsIDOMNode* aDOMNode,
+                                              nsIArray* aTransferableArray,
+                                              nsIScriptableRegion* aRegion,
+                                              uint32_t aActionType,
+                                              nsIDOMNode* aImage,
+                                              int32_t aImageX, int32_t aImageY,
+                                              nsIDOMDragEvent* aDragEvent,
+                                              nsIDOMDataTransfer* aDataTransfer)
+{
+  NS_ENSURE_TRUE(aDragEvent, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(aDataTransfer, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  mDataTransfer = aDataTransfer;
+  mSelection = nullptr;
+  mHasImage = true;
+  mDragPopup = nullptr;
+  mImage = aImage;
+  mImageOffset = CSSIntPoint(aImageX, aImageY);
+
+  aDragEvent->GetScreenX(&mScreenPosition.x);
+  aDragEvent->GetScreenY(&mScreenPosition.y);
+  aDragEvent->GetMozInputSource(&mInputSource);
+
+  nsresult rv = InvokeDragSession(aDOMNode, aTransferableArray,
+                                  aRegion, aActionType,
+                                  nsIContentPolicy::TYPE_INTERNAL_IMAGE);
+
+  if (NS_FAILED(rv)) {
+    mImage = nullptr;
+    mHasImage = false;
+    mDataTransfer = nullptr;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSessionWithSelection(nsISelection* aSelection,
+                                                  nsIArray* aTransferableArray,
+                                                  uint32_t aActionType,
+                                                  nsIDOMDragEvent* aDragEvent,
+                                                  nsIDOMDataTransfer* aDataTransfer)
+{
+  NS_ENSURE_TRUE(aSelection, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(aDragEvent, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  mDataTransfer = aDataTransfer;
+  mSelection = aSelection;
+  mHasImage = true;
+  mDragPopup = nullptr;
+  mImage = nullptr;
+  mImageOffset = CSSIntPoint();
+
+  aDragEvent->GetScreenX(&mScreenPosition.x);
+  aDragEvent->GetScreenY(&mScreenPosition.y);
+  aDragEvent->GetMozInputSource(&mInputSource);
+
+  // just get the focused node from the selection
+  // XXXndeakin this should actually be the deepest node that contains both
+  // endpoints of the selection
+  nsCOMPtr<nsIDOMNode> node;
+  aSelection->GetFocusNode(getter_AddRefs(node));
+
+  nsresult rv = InvokeDragSession(node, aTransferableArray,
+                                  nullptr, aActionType,
+                                  nsIContentPolicy::TYPE_OTHER);
+
+  if (NS_FAILED(rv)) {
+    mHasImage = false;
+    mSelection = nullptr;
+    mDataTransfer = nullptr;
+  }
+
+  return rv;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetCurrentSession(nsIDragSession ** aSession)
+{
+  if (!aSession)
+    return NS_ERROR_INVALID_ARG;
+
+  // "this" also implements a drag session, so say we are one but only
+  // if there is currently a drag going on.
+  if (!mSuppressLevel && mDoingDrag) {
+    *aSession = this;
+    NS_ADDREF(*aSession);      // addRef because we're a "getter"
+  }
+  else
+    *aSession = nullptr;
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::StartDragSession()
+{
+  if (mDoingDrag) {
+    return NS_ERROR_FAILURE;
+  }
+  mDoingDrag = true;
+  // By default dispatch drop also to content.
+  mOnlyChromeDrop = false;
+
+  return NS_OK;
+}
+
+void
+nsBaseDragService::OpenDragPopup()
+{
+  if (mDragPopup) {
+    nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+    if (pm) {
+      pm->ShowPopupAtScreen(mDragPopup, mScreenPosition.x - mImageOffset.x,
+                            mScreenPosition.y - mImageOffset.y, false, nullptr);
+    }
+  }
+}
+
+int32_t
+nsBaseDragService::TakeChildProcessDragAction()
+{
+  // If the last event was dispatched to the child process, use the drag action
+  // assigned from it instead and return it. DRAGDROP_ACTION_UNINITIALIZED is
+  // returned otherwise.
+  int32_t retval = DRAGDROP_ACTION_UNINITIALIZED;
+  if (TakeDragEventDispatchedToChildProcess() &&
+      mDragActionFromChildProcess != DRAGDROP_ACTION_UNINITIALIZED) {
+    retval = mDragActionFromChildProcess;
+  }
+
+  return retval;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::EndDragSession(bool aDoneDrag)
+{
+  if (!mDoingDrag) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (aDoneDrag && !mSuppressLevel) {
+    FireDragEventAtSource(eDragEnd);
+  }
+
+  if (mDragPopup) {
+    nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+    if (pm) {
+      pm->HidePopup(mDragPopup, false, true, false, false);
+    }
+  }
+
+  for (uint32_t i = 0; i < mChildProcesses.Length(); ++i) {
+    mozilla::Unused << mChildProcesses[i]->SendEndDragSession(aDoneDrag,
+                                                              mUserCancelled,
+                                                              mEndDragPoint);
+  }
+  mChildProcesses.Clear();
+
+  // mDataTransfer and the items it owns are going to die anyway, but we
+  // explicitly deref the contained data here so that we don't have to wait for
+  // CC to reclaim the memory.
+  if (XRE_IsParentProcess()) {
+    DiscardInternalTransferData();
+  }
+
+  mDoingDrag = false;
+  mCanDrop = false;
+
+  // release the source we've been holding on to.
+  mSourceDocument = nullptr;
+  mSourceNode = nullptr;
+  mSelection = nullptr;
+  mDataTransfer = nullptr;
+  mHasImage = false;
+  mUserCancelled = false;
+  mDragPopup = nullptr;
+  mImage = nullptr;
+  mImageOffset = CSSIntPoint();
+  mScreenPosition = CSSIntPoint();
+  mEndDragPoint = LayoutDeviceIntPoint(0, 0);
+  mInputSource = nsIDOMMouseEvent::MOZ_SOURCE_MOUSE;
+
+  return NS_OK;
+}
+
+void
+nsBaseDragService::DiscardInternalTransferData()
+{
+  if (mDataTransfer && mSourceNode) {
+    MOZ_ASSERT(!!DataTransfer::Cast(mDataTransfer));
+
+    DataTransferItemList* items = DataTransfer::Cast(mDataTransfer)->Items();
+    for (size_t i = 0; i < items->Length(); i++) {
+      bool found;
+      DataTransferItem* item = items->IndexedGetter(i, found);
+
+      // Non-OTHER items may still be needed by JS. Skip them.
+      if (!found || item->Kind() != DataTransferItem::KIND_OTHER) {
+        continue;
+      }
+
+      nsCOMPtr<nsIVariant> variant = item->DataNoSecurityCheck();
+      nsCOMPtr<nsIWritableVariant> writable = do_QueryInterface(variant);
+
+      if (writable) {
+        writable->SetAsEmpty();
+      }
+    }
+  }
+}
+
+NS_IMETHODIMP
+nsBaseDragService::FireDragEventAtSource(EventMessage aEventMessage)
+{
+  if (mSourceNode && !mSuppressLevel) {
+    nsCOMPtr<nsIDocument> doc = do_QueryInterface(mSourceDocument);
+    if (doc) {
+      nsCOMPtr<nsIPresShell> presShell = doc->GetShell();
+      if (presShell) {
+        nsEventStatus status = nsEventStatus_eIgnore;
+        WidgetDragEvent event(true, aEventMessage, nullptr);
+        event.inputSource = mInputSource;
+        if (aEventMessage == eDragEnd) {
+          event.mRefPoint = mEndDragPoint;
+          event.mUserCancelled = mUserCancelled;
+        }
+
+        // Send the drag event to APZ, which needs to know about them to be
+        // able to accurately detect the end of a drag gesture.
+        if (nsPresContext* presContext = presShell->GetPresContext()) {
+          if (nsCOMPtr<nsIWidget> widget = presContext->GetRootWidget()) {
+            widget->DispatchEventToAPZOnly(&event);
+          }
+        }
+
+        nsCOMPtr<nsIContent> content = do_QueryInterface(mSourceNode);
+        return presShell->HandleDOMEventWithTarget(content, &event, &status);
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+/* This is used by Windows and Mac to update the position of a popup being
+ * used as a drag image during the drag. This isn't used on GTK as it manages
+ * the drag popup itself.
+ */
+NS_IMETHODIMP
+nsBaseDragService::DragMoved(int32_t aX, int32_t aY)
+{
+  if (mDragPopup) {
+    nsIFrame* frame = mDragPopup->GetPrimaryFrame();
+    if (frame && frame->GetType() == nsGkAtoms::menuPopupFrame) {
+      CSSIntPoint cssPos = RoundedToInt(LayoutDeviceIntPoint(aX, aY) /
+          frame->PresContext()->CSSToDevPixelScale()) - mImageOffset;
+      (static_cast<nsMenuPopupFrame *>(frame))->MoveTo(cssPos, true);
+    }
+  }
+
+  return NS_OK;
+}
+
+static nsIPresShell*
+GetPresShellForContent(nsIDOMNode* aDOMNode)
+{
+  nsCOMPtr<nsIContent> content = do_QueryInterface(aDOMNode);
+  if (!content)
+    return nullptr;
+
+  nsCOMPtr<nsIDocument> document = content->GetUncomposedDoc();
+  if (document) {
+    document->FlushPendingNotifications(Flush_Display);
+
+    return document->GetShell();
+  }
+
+  return nullptr;
+}
+
+nsresult
+nsBaseDragService::DrawDrag(nsIDOMNode* aDOMNode,
+                            nsIScriptableRegion* aRegion,
+                            CSSIntPoint aScreenPosition,
+                            LayoutDeviceIntRect* aScreenDragRect,
+                            RefPtr<SourceSurface>* aSurface,
+                            nsPresContext** aPresContext)
+{
+  *aSurface = nullptr;
+  *aPresContext = nullptr;
+
+  // use a default size, in case of an error.
+  aScreenDragRect->MoveTo(aScreenPosition.x - mImageOffset.x,
+                          aScreenPosition.y - mImageOffset.y);
+  aScreenDragRect->SizeTo(1, 1);
+
+  // if a drag image was specified, use that, otherwise, use the source node
+  nsCOMPtr<nsIDOMNode> dragNode = mImage ? mImage.get() : aDOMNode;
+
+  // get the presshell for the node being dragged. If the drag image is not in
+  // a document or has no frame, get the presshell from the source drag node
+  nsIPresShell* presShell = GetPresShellForContent(dragNode);
+  if (!presShell && mImage)
+    presShell = GetPresShellForContent(aDOMNode);
+  if (!presShell)
+    return NS_ERROR_FAILURE;
+
+  *aPresContext = presShell->GetPresContext();
+
+  nsCOMPtr<nsIFrameLoaderOwner> flo = do_QueryInterface(dragNode);
+  if (flo) {
+    RefPtr<nsFrameLoader> fl = flo->GetFrameLoader();
+    if (fl) {
+      mozilla::dom::TabParent* tp =
+        static_cast<mozilla::dom::TabParent*>(fl->GetRemoteBrowser());
+      if (tp && tp->TakeDragVisualization(*aSurface, aScreenDragRect)) {
+        if (mImage) {
+          // Just clear the surface if chrome has overridden it with an image.
+          *aSurface = nullptr;
+        }
+
+        return NS_OK;
+      }
+    }
+  }
+
+  // convert mouse position to dev pixels of the prescontext
+  CSSIntPoint screenPosition(aScreenPosition);
+  screenPosition.x -= mImageOffset.x;
+  screenPosition.y -= mImageOffset.y;
+  LayoutDeviceIntPoint screenPoint = ConvertToUnscaledDevPixels(*aPresContext, screenPosition);
+  aScreenDragRect->x = screenPoint.x;
+  aScreenDragRect->y = screenPoint.y;
+
+  // check if drag images are disabled
+  bool enableDragImages = Preferences::GetBool(DRAGIMAGES_PREF, true);
+
+  // didn't want an image, so just set the screen rectangle to the frame size
+  if (!enableDragImages || !mHasImage) {
+    // if a region was specified, set the screen rectangle to the area that
+    // the region occupies
+    nsIntRect dragRect;
+    if (aRegion) {
+      // the region's coordinates are relative to the root frame
+      aRegion->GetBoundingBox(&dragRect.x, &dragRect.y, &dragRect.width, &dragRect.height);
+
+      nsIFrame* rootFrame = presShell->GetRootFrame();
+      nsIntRect screenRect = rootFrame->GetScreenRect();
+      dragRect.MoveBy(screenRect.TopLeft());
+    }
+    else {
+      // otherwise, there was no region so just set the rectangle to
+      // the size of the primary frame of the content.
+      nsCOMPtr<nsIContent> content = do_QueryInterface(dragNode);
+      nsIFrame* frame = content->GetPrimaryFrame();
+      if (frame) {
+        dragRect = frame->GetScreenRect();
+      }
+    }
+
+    dragRect = ToAppUnits(dragRect, nsPresContext::AppUnitsPerCSSPixel()).
+                          ToOutsidePixels((*aPresContext)->AppUnitsPerDevPixel());
+    aScreenDragRect->SizeTo(dragRect.width, dragRect.height);
+    return NS_OK;
+  }
+
+  // draw the image for selections
+  if (mSelection) {
+    LayoutDeviceIntPoint pnt(aScreenDragRect->TopLeft());
+    *aSurface = presShell->RenderSelection(mSelection, pnt, aScreenDragRect,
+        mImage ? 0 : nsIPresShell::RENDER_AUTO_SCALE);
+    return NS_OK;
+  }
+
+  // if a custom image was specified, check if it is an image node and draw
+  // using the source rather than the displayed image. But if mImage isn't
+  // an image or canvas, fall through to RenderNode below.
+  if (mImage) {
+    nsCOMPtr<nsIContent> content = do_QueryInterface(dragNode);
+    HTMLCanvasElement *canvas = HTMLCanvasElement::FromContentOrNull(content);
+    if (canvas) {
+      return DrawDragForImage(*aPresContext, nullptr, canvas, aScreenDragRect, aSurface);
+    }
+
+    nsCOMPtr<nsIImageLoadingContent> imageLoader = do_QueryInterface(dragNode);
+    // for image nodes, create the drag image from the actual image data
+    if (imageLoader) {
+      return DrawDragForImage(*aPresContext, imageLoader, nullptr, aScreenDragRect, aSurface);
+    }
+
+    // If the image is a popup, use that as the image. This allows custom drag
+    // images that can change during the drag, but means that any platform
+    // default image handling won't occur.
+    // XXXndeakin this should be chrome-only
+
+    nsIFrame* frame = content->GetPrimaryFrame();
+    if (frame && frame->GetType() == nsGkAtoms::menuPopupFrame) {
+      mDragPopup = content;
+    }
+  }
+
+  if (!mDragPopup) {
+    // otherwise, just draw the node
+    nsIntRegion clipRegion;
+    uint32_t renderFlags = mImage ? 0 : nsIPresShell::RENDER_AUTO_SCALE;
+    if (aRegion) {
+      aRegion->GetRegion(&clipRegion);
+    }
+
+    if (renderFlags) {
+      nsCOMPtr<nsIDOMNode> child;
+      nsCOMPtr<nsIDOMNodeList> childList;
+      uint32_t length;
+      uint32_t count = 0;
+      nsAutoString childNodeName;
+
+      if (NS_SUCCEEDED(dragNode->GetChildNodes(getter_AddRefs(childList))) &&
+          NS_SUCCEEDED(childList->GetLength(&length))) {
+        // check every childnode for being a img-tag
+        while (count < length) {
+          if (NS_FAILED(childList->Item(count, getter_AddRefs(child))) ||
+              NS_FAILED(child->GetNodeName(childNodeName))) {
+            break;
+          }
+          // here the node is checked for being a img-tag
+          if (childNodeName.LowerCaseEqualsLiteral("img")) {
+            // if the dragnnode contains a image, set RENDER_IS_IMAGE flag
+            renderFlags = renderFlags | nsIPresShell::RENDER_IS_IMAGE;
+            break;
+          }
+          count++;
+        }
+      }
+    }
+    LayoutDeviceIntPoint pnt(aScreenDragRect->TopLeft());
+    *aSurface = presShell->RenderNode(dragNode, aRegion ? &clipRegion : nullptr,
+                                      pnt, aScreenDragRect,
+                                      renderFlags);
+  }
+
+  // If an image was specified, reset the position from the offset that was supplied.
+  if (mImage) {
+    aScreenDragRect->x = screenPoint.x;
+    aScreenDragRect->y = screenPoint.y;
+  }
+
+  return NS_OK;
+}
+
+nsresult
+nsBaseDragService::DrawDragForImage(nsPresContext* aPresContext,
+                                    nsIImageLoadingContent* aImageLoader,
+                                    HTMLCanvasElement* aCanvas,
+                                    LayoutDeviceIntRect* aScreenDragRect,
+                                    RefPtr<SourceSurface>* aSurface)
+{
+  nsCOMPtr<imgIContainer> imgContainer;
+  if (aImageLoader) {
+    nsCOMPtr<imgIRequest> imgRequest;
+    nsresult rv = aImageLoader->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
+                                          getter_AddRefs(imgRequest));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!imgRequest)
+      return NS_ERROR_NOT_AVAILABLE;
+
+    rv = imgRequest->GetImage(getter_AddRefs(imgContainer));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!imgContainer)
+      return NS_ERROR_NOT_AVAILABLE;
+
+    // use the size of the image as the size of the drag image
+    int32_t imageWidth, imageHeight;
+    rv = imgContainer->GetWidth(&imageWidth);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = imgContainer->GetHeight(&imageHeight);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    aScreenDragRect->width = aPresContext->CSSPixelsToDevPixels(imageWidth);
+    aScreenDragRect->height = aPresContext->CSSPixelsToDevPixels(imageHeight);
+  }
+  else {
+    // XXX The canvas size should be converted to dev pixels.
+    NS_ASSERTION(aCanvas, "both image and canvas are null");
+    nsIntSize sz = aCanvas->GetSize();
+    aScreenDragRect->width = sz.width;
+    aScreenDragRect->height = sz.height;
+  }
+
+  nsIntSize destSize;
+  destSize.width = aScreenDragRect->width;
+  destSize.height = aScreenDragRect->height;
+  if (destSize.width == 0 || destSize.height == 0)
+    return NS_ERROR_FAILURE;
+
+  nsresult result = NS_OK;
+  if (aImageLoader) {
+    RefPtr<DrawTarget> dt =
+      gfxPlatform::GetPlatform()->
+        CreateOffscreenContentDrawTarget(destSize,
+                                         SurfaceFormat::B8G8R8A8);
+    if (!dt || !dt->IsValid())
+      return NS_ERROR_FAILURE;
+
+    RefPtr<gfxContext> ctx = gfxContext::CreateOrNull(dt);
+    if (!ctx)
+      return NS_ERROR_FAILURE;
+
+    DrawResult res =
+      imgContainer->Draw(ctx, destSize, ImageRegion::Create(destSize),
+                         imgIContainer::FRAME_CURRENT,
+                         SamplingFilter::GOOD, /* no SVGImageContext */ Nothing(),
+                         imgIContainer::FLAG_SYNC_DECODE);
+    if (res == DrawResult::BAD_IMAGE || res == DrawResult::BAD_ARGS) {
+      return NS_ERROR_FAILURE;
+    }
+    *aSurface = dt->Snapshot();
+  } else {
+    *aSurface = aCanvas->GetSurfaceSnapshot();
+  }
+
+  return result;
+}
+
+LayoutDeviceIntPoint
+nsBaseDragService::ConvertToUnscaledDevPixels(nsPresContext* aPresContext,
+                                              CSSIntPoint aScreenPosition)
+{
+  int32_t adj = aPresContext->DeviceContext()->AppUnitsPerDevPixelAtUnitFullZoom();
+  return LayoutDeviceIntPoint(nsPresContext::CSSPixelsToAppUnits(aScreenPosition.x) / adj,
+                              nsPresContext::CSSPixelsToAppUnits(aScreenPosition.y) / adj);
+}
+
+NS_IMETHODIMP
+nsBaseDragService::Suppress()
+{
+  EndDragSession(false);
+  ++mSuppressLevel;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::Unsuppress()
+{
+  --mSuppressLevel;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::UserCancelled()
+{
+  mUserCancelled = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::UpdateDragEffect()
+{
+  mDragActionFromChildProcess = mDragAction;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::DragEventDispatchedToChildProcess()
+{
+  mDragEventDispatchedToChildProcess = true;
+  return NS_OK;
+}
+
+bool
+nsBaseDragService::MaybeAddChildProcess(mozilla::dom::ContentParent* aChild)
+{
+  if (!mChildProcesses.Contains(aChild)) {
+    mChildProcesses.AppendElement(aChild);
+    return true;
+  }
+  return false;
+}