Bug 1404789 - Stop reconstructing frames for the whole shadow root each time content is inserted in a shadow tree

* Cleanup a bit the ShadowRoot code
* Privatize ShadowRoot methods
* When the shadow tree distribution changes, post a restyle + reframe
* Simplify ShadowRoot::IsPooledNode
* Be a bit better at detecting distribution changes

Tag #1375

2 files changed, 3 insertions, 12 deletions

diff --git a/dom/html/HTMLContentElement.cpp b/dom/html/HTMLContentElement.cpp
index 158f8d0ce9..15d79c761a 100644
--- a/dom/html/HTMLContentElement.cpp
+++ b/dom/html/HTMLContentElement.cpp
@@ -248,8 +248,7 @@ HTMLContentElement::AfterSetAttr(int32_t aNamespaceID, nsIAtom* aName,
         }
       }
 
-      ShadowRoot* containingShadow = GetContainingShadow();
-      if (containingShadow) {
+      if (ShadowRoot* containingShadow = GetContainingShadow()) {
         containingShadow->DistributeAllNodes();
       }
     } else {
@@ -258,8 +257,7 @@ HTMLContentElement::AfterSetAttr(int32_t aNamespaceID, nsIAtom* aName,
       mValidSelector = true;
       mSelectorList = nullptr;
 
-      ShadowRoot* containingShadow = GetContainingShadow();
-      if (containingShadow) {
+      if (ShadowRoot* containingShadow = GetContainingShadow()) {
         containingShadow->DistributeAllNodes();
       }
     }
diff --git a/dom/html/HTMLContentElement.h b/dom/html/HTMLContentElement.h
index d2491a7928..630e26d17d 100644
--- a/dom/html/HTMLContentElement.h
+++ b/dom/html/HTMLContentElement.h
@@ -29,14 +29,7 @@ public:
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLContentElement,
                                            nsGenericHTMLElement)
 
-  static HTMLContentElement* FromContent(nsIContent* aContent)
-  {
-    if (aContent->IsHTMLContentElement()) {
-      return static_cast<HTMLContentElement*>(aContent);
-    }
-
-    return nullptr;
-  }
+  NS_IMPL_FROMCONTENT_HELPER(HTMLContentElement, IsHTMLContentElement())
 
   virtual bool IsHTMLContentElement() const override { return true; }