DOM-based SVG resource tracking

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

Index: third_party/WebKit/Source/core/layout/svg/SVGResourcesCache.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/SVGResourcesCache.cpp b/third_party/WebKit/Source/core/layout/svg/SVGResourcesCache.cpp
index dc9cdff976402988c24be236fe841681199c2aaf..d0a4d7d881c4b72d254c3c915d5fd9be6f1973c1 100644
--- a/third_party/WebKit/Source/core/layout/svg/SVGResourcesCache.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/SVGResourcesCache.cpp
@@ -70,8 +70,13 @@ void SVGResourcesCache::RemoveResourcesFromLayoutObject(LayoutObject* object) {
   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) {
@@ -150,6 +155,26 @@ void SVGResourcesCache::ClientStyleChanged(LayoutObject* layout_object,
       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())