DOM-based SVG resource tracking

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

 /*
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 52 matching lines @@
 void SVGResourcesCache::RemoveResourcesFromLayoutObject(LayoutObject* object) {
   std::unique_ptr<SVGResources> resources = cache_.Take(object);
   if (!resources)
     return;
 
   // Walk resources and unregister the layout object as a client of each
   // resource.
   HashSet<LayoutSVGResourceContainer*> resource_set;
   resources->BuildSetOfResources(resource_set);
 
+  bool did_empty_client_set = false;
   for (auto* resource_container : resource_set)
-    resource_container->RemoveClient(object);
+    did_empty_client_set |= resource_container->RemoveClient(object);
+
+  // Remove any registrations that became empty after the above.
+  if (did_empty_client_set)
+    SVGResources::RemoveUnreferencedResources(*object);
 }
 
 static inline SVGResourcesCache& ResourcesCache(Document& document) {
   return document.AccessSVGExtensions().ResourcesCache();
 }
 
 SVGResources* SVGResourcesCache::CachedResourcesForLayoutObject(
     const LayoutObject* layout_object) {
   DCHECK(layout_object);
   return ResourcesCache(layout_object->GetDocument()).cache_.at(layout_object);
@@ skipping 58 matching lines @@
   // If this layoutObject is the child of ResourceContainer and it require
   // repainting that changes of CSS properties such as 'visibility',
   // request repainting.
   bool needs_layout = diff.NeedsFullPaintInvalidation() &&
                       IsLayoutObjectOfResourceContainer(layout_object);
 
   LayoutSVGResourceContainer::MarkForLayoutAndParentResourceInvalidation(
       layout_object, needs_layout);
 }
 
+void SVGResourcesCache::ResourceReferenceChanged(LayoutObject& layout_object) {
+  DCHECK(layout_object.IsSVG());
+  DCHECK(layout_object.GetNode());
+  DCHECK(layout_object.GetNode()->IsSVGElement());
+
+  if (!layout_object.Parent())
+    return;
+
+  // Only LayoutObjects that can actually have resources should be pending and
+  // hence be able to call this method.
+  DCHECK(LayoutObjectCanHaveResources(&layout_object));
+
+  SVGResourcesCache& cache = ResourcesCache(layout_object.GetDocument());
+  cache.RemoveResourcesFromLayoutObject(&layout_object);
+  cache.AddResourcesFromLayoutObject(&layout_object, layout_object.StyleRef());
+
+  LayoutSVGResourceContainer::MarkForLayoutAndParentResourceInvalidation(
+      &layout_object, true);
+}
+
 void SVGResourcesCache::ClientWasAddedToTree(LayoutObject* layout_object,
                                              const ComputedStyle& new_style) {
   if (!layout_object->GetNode())
     return;
   LayoutSVGResourceContainer::MarkForLayoutAndParentResourceInvalidation(
       layout_object, false);
 
   if (!LayoutObjectCanHaveResources(layout_object))
     return;
   SVGResourcesCache& cache = ResourcesCache(layout_object->GetDocument());
@@ skipping 37 matching lines @@
     const ComputedStyle& style) {
   DCHECK(LayoutObjectCanHaveResources(&layout_object_));
   if (styles_are_equal_)
     return;
   SVGResourcesCache& cache = ResourcesCache(layout_object_.GetDocument());
   cache.RemoveResourcesFromLayoutObject(&layout_object_);
   cache.AddResourcesFromLayoutObject(&layout_object_, style);
 }
 
 }  // namespace blink