DOM-based SVG resource tracking

third_party/WebKit/Source/core/layout/svg/SVGResources.cpp

Index: third_party/WebKit/Source/core/layout/svg/SVGResources.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/SVGResources.cpp b/third_party/WebKit/Source/core/layout/svg/SVGResources.cpp
index d2f4c08b6d4cd55a8fceab49ccad638cc11cc759..7c08f2fbde7816aeca1ca89bb80ecf377eca5f45 100644
--- a/third_party/WebKit/Source/core/layout/svg/SVGResources.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/SVGResources.cpp
@@ -157,12 +157,15 @@ template <typename ContainerType>
 ContainerType* AttachToResource(SVGTreeScopeResources& tree_scope_resources,
                                 const AtomicString& id,
                                 SVGElement& element) {
-  if (LayoutSVGResourceContainer* container =
-          tree_scope_resources.ResourceById(id)) {
+  SVGTreeScopeResources::Resource* resource =
+      tree_scope_resources.ResourceForId(id);
+  if (!resource)
+    return nullptr;
+  if (LayoutSVGResourceContainer* container = resource->ResourceContainer()) {
     if (IsResourceOfType<ContainerType>(container))
       return static_cast<ContainerType*>(container);
   }
-  tree_scope_resources.AddPendingResource(id, element);
+  resource->AddWatch(element);
   return nullptr;
 }
 }
@@ -279,6 +282,22 @@ std::unique_ptr<SVGResources> SVGResources::BuildResources(
                                                        : std::move(resources);
 }
 
+void SVGResources::RemoveUnreferencedResources(const LayoutObject& object) {
+  SVGTreeScopeResources& tree_scope_resources =
+      ToSVGElement(*object.GetNode())
+          .TreeScopeForIdResolution()
+          .EnsureSVGTreeScopedResources();
+  tree_scope_resources.RemoveUnreferencedResources();
+}
+
+void SVGResources::RemoveWatchesForElement(Element& element) {
+  SECURITY_DCHECK(element.IsSVGElement());
+  SVGElement& svg_element = ToSVGElement(element);
+  SVGTreeScopeResources& tree_scope_resources =
+      svg_element.TreeScopeForIdResolution().EnsureSVGTreeScopedResources();
+  tree_scope_resources.RemoveWatchesForElement(svg_element);
+}
+
 void SVGResources::LayoutIfNeeded() {
   if (clipper_filter_masker_data_) {
     if (LayoutSVGResourceClipper* clipper =