Bug 1393791 - Move SVG Use anonymous content to the frame. r=emilio

This brings it into alignment with what everything else does.

MozReview-Commit-ID: 2A9p8umHnKi

dom/svg/SVGUseElement.cpp

@@ -17,6 +17,7 @@
 #include "nsIURI.h"
 #include "mozilla/URLExtraData.h"
 #include "nsSVGEffects.h"
+#include "nsSVGUseFrame.h"
 
 NS_IMPL_NS_NEW_NAMESPACED_SVG_ELEMENT(Use)
 
@@ -55,13 +56,11 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(SVGUseElement,
                                                 SVGUseElementBase)
   nsAutoScriptBlocker scriptBlocker;
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mOriginal)
-  tmp->DestroyAnonymousContent();
   tmp->UnlinkSource();
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(SVGUseElement,
                                                   SVGUseElementBase)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOriginal)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mClone)
   tmp->mSource.Traverse(&cb);
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
@@ -213,11 +212,9 @@ SVGUseElement::NodeWillBeDestroyed(const nsINode *aNode)
 
 //----------------------------------------------------------------------
 
-nsIContent*
+already_AddRefed<nsIContent>
 SVGUseElement::CreateAnonymousContent()
 {
-  mClone = nullptr;
-
   if (mSource.get()) {
     mSource.get()->RemoveMutationObserver(this);
   }
@@ -293,18 +290,17 @@ SVGUseElement::CreateAnonymousContent()
                                      do_AddRef(NodePrincipal()));
 
   targetContent->AddMutationObserver(this);
-  mClone = newcontent;
 
 #ifdef DEBUG
   // Our anonymous clone can get restyled by various things
   // (e.g. SMIL).  Reconstructing its frame is OK, though, because
   // it's going to be our _only_ child in the frame tree, so can't get
   // mis-ordered with anything.
-  mClone->SetProperty(nsGkAtoms::restylableAnonymousNode,
-                      reinterpret_cast<void*>(true));
+  newcontent->SetProperty(nsGkAtoms::restylableAnonymousNode,
+                          reinterpret_cast<void*>(true));
 #endif // DEBUG
 
-  return mClone;
+  return newcontent.forget();
 }
 
 nsIURI*
@@ -317,16 +313,14 @@ SVGUseElement::GetSourceDocURI()
   return targetContent->OwnerDoc()->GetDocumentURI();
 }
 
-void
-SVGUseElement::DestroyAnonymousContent()
-{
-  nsContentUtils::DestroyAnonymousContent(&mClone);
-}
-
 bool
 SVGUseElement::OurWidthAndHeightAreUsed() const
 {
-  return mClone && mClone->IsAnyOfSVGElements(nsGkAtoms::svg, nsGkAtoms::symbol);
+  auto* frame = GetFrame();
+  if (!frame || !frame->GetContentClone()) {
+    return false;
+  }
+  return frame->GetContentClone()->IsAnyOfSVGElements(nsGkAtoms::svg, nsGkAtoms::symbol);
 }
 
 //----------------------------------------------------------------------
@@ -339,15 +333,18 @@ SVGUseElement::SyncWidthOrHeight(nsIAtom* aName)
                "The clue is in the function name");
   NS_ASSERTION(OurWidthAndHeightAreUsed(), "Don't call this");
 
+  auto* frame = GetFrame();
+  nsIContent* clone = frame ? frame->GetContentClone() : nullptr;
+
   if (OurWidthAndHeightAreUsed()) {
-    nsSVGElement *target = static_cast<nsSVGElement*>(mClone.get());
+    auto* target = static_cast<nsSVGElement*>(clone);
     uint32_t index = *sLengthInfo[ATTR_WIDTH].mName == aName ? ATTR_WIDTH : ATTR_HEIGHT;
 
     if (mLengthAttributes[index].IsExplicitlySet()) {
       target->SetLength(aName, mLengthAttributes[index]);
       return;
     }
-    if (mClone->IsSVGElement(nsGkAtoms::svg)) {
+    if (clone->IsSVGElement(nsGkAtoms::svg)) {
       // Our width/height attribute is now no longer explicitly set, so we
       // need to revert the clone's width/height to the width/height of the
       // content that's being cloned.
@@ -474,6 +471,14 @@ SVGUseElement::GetStringInfo()
                               ArrayLength(sStringInfo));
 }
 
+nsSVGUseFrame*
+SVGUseElement::GetFrame() const
+{
+  nsIFrame* frame = GetPrimaryFrame();
+  MOZ_ASSERT_IF(frame, frame->IsSVGUseFrame());
+  return static_cast<nsSVGUseFrame*>(frame);
+}
+
 //----------------------------------------------------------------------
 // nsIContent methods
 

dom/svg/SVGUseElement.h

@@ -57,9 +57,7 @@ class SVGUseElement final : public SVGUseElementBase,
   NS_DECL_NSIMUTATIONOBSERVER_NODEWILLBEDESTROYED
 
   // for nsSVGUseFrame's nsIAnonymousContentCreator implementation.
-  nsIContent* CreateAnonymousContent();
-  nsIContent* GetAnonymousContent() const { return mClone; }
-  void DestroyAnonymousContent();
+  already_AddRefed<nsIContent> CreateAnonymousContent();
 
   // nsSVGElement specializations:
   virtual gfxMatrix PrependLocalTransformsTo(
@@ -98,6 +96,8 @@ class SVGUseElement final : public SVGUseElementBase,
     SVGUseElement* mContainer;
   };
 
+  nsSVGUseFrame* GetFrame() const;
+
   virtual LengthAttributesInfo GetLengthInfo() override;
   virtual StringAttributesInfo GetStringInfo() override;
 

layout/svg/nsSVGUseFrame.cpp

@@ -4,6 +4,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsSVGUseFrame.h"
+#include "nsContentUtils.h"
 
 #include "mozilla/dom/SVGUseElement.h"
 #include "nsContentList.h"
@@ -101,9 +102,8 @@ nsSVGUseFrame::AttributeChanged(int32_t         aNameSpaceID,
 void
 nsSVGUseFrame::DestroyFrom(nsIFrame* aDestructRoot)
 {
-  RefPtr<SVGUseElement> use = static_cast<SVGUseElement*>(GetContent());
+  nsContentUtils::DestroyAnonymousContent(&mContentClone);
   nsSVGGFrame::DestroyFrom(aDestructRoot);
-  use->DestroyAnonymousContent();
 }
 
 
@@ -168,23 +168,20 @@ nsSVGUseFrame::CreateAnonymousContent(nsTArray<ContentInfo>& aElements)
 {
   SVGUseElement *use = static_cast<SVGUseElement*>(GetContent());
 
-  nsIContent* clone = use->CreateAnonymousContent();
+  mContentClone = use->CreateAnonymousContent();
   nsLayoutUtils::PostRestyleEvent(
     use, nsRestyleHint(0), nsChangeHint_InvalidateRenderingObservers);
-  if (!clone)
+  if (!mContentClone)
     return NS_ERROR_FAILURE;
-  if (!aElements.AppendElement(clone))
-    return NS_ERROR_OUT_OF_MEMORY;
+  aElements.AppendElement(mContentClone);
   return NS_OK;
 }
 
 void
 nsSVGUseFrame::AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
                                         uint32_t aFilter)
 {
-  SVGUseElement *use = static_cast<SVGUseElement*>(GetContent());
-  nsIContent* clone = use->GetAnonymousContent();
-  if (clone) {
-    aElements.AppendElement(clone);
+  if (mContentClone) {
+    aElements.AppendElement(mContentClone);
   }
 }

layout/svg/nsSVGUseFrame.h

@@ -55,8 +55,11 @@ class nsSVGUseFrame final
   void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
                                 uint32_t aFilter) override;
 
+  nsIContent* GetContentClone() { return mContentClone.get(); }
+
 private:
   bool mHasValidDimensions;
+  nsCOMPtr<nsIContent> mContentClone;
 };
 
 #endif // __NS_SVGUSEFRAME_H__