Improve handling of duplicate id's for SVG resources

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

Index: third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceContainer.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceContainer.cpp b/third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceContainer.cpp
index f50247e0199b30ce70d3f2634876f15ba3c8931e..cf36a430aa6198a3035699bd6d8320e0787262d6 100644
--- a/third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceContainer.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceContainer.cpp
@@ -67,31 +67,22 @@ void LayoutSVGResourceContainer::notifyContentChanged() {
 }
 
 void LayoutSVGResourceContainer::willBeDestroyed() {
-  // Detach all clients referring to this resource. If the resource itself is
-  // a client, it will be detached from any such resources by the call to
-  // LayoutSVGHiddenContainer::willBeDestroyed() below.
-  detachAllClients();
-
   LayoutSVGHiddenContainer::willBeDestroyed();
-  if (!m_registered)
-    return;
   svgTreeScopeResourcesFromElement(element()).removeResource(
-      element()->getIdAttribute());
+      element()->getIdAttribute(), this);
+  DCHECK(m_clients.isEmpty());
 }
 
 void LayoutSVGResourceContainer::styleDidChange(StyleDifference diff,
                                                 const ComputedStyle* oldStyle) {
   LayoutSVGHiddenContainer::styleDidChange(diff, oldStyle);
-
-  if (m_registered)
-    return;
-  m_registered = true;
   svgTreeScopeResourcesFromElement(element()).updateResource(
       element()->getIdAttribute(), this);
 }
 
-void LayoutSVGResourceContainer::detachAllClients() {
-  const AtomicString& id = element()->getIdAttribute();
+void LayoutSVGResourceContainer::detachAllClients(const AtomicString& toId) {
+  removeAllClientsFromCache();
+
   for (auto* client : m_clients) {
     // Unlink the resource from the client's SVGResources. (The actual
     // removal will be signaled after processing all the clients.)
@@ -104,22 +95,15 @@ void LayoutSVGResourceContainer::detachAllClients() {
     // Add a pending resolution based on the id of the old resource.
     Element* clientElement = toElement(client->node());
     svgTreeScopeResourcesFromElement(clientElement)
-        .addPendingResource(id, *clientElement);
+        .addPendingResource(toId, *clientElement);
   }
-
-  removeAllClientsFromCache();
+  m_clients.clear();
 }
 
 void LayoutSVGResourceContainer::idChanged(const AtomicString& oldId,
                                            const AtomicString& newId) {
-  // Invalidate all our current clients.
-  removeAllClientsFromCache();
-
-  // Remove old id, that is guaranteed to be present in cache.
-  SVGTreeScopeResources& treeScopeResources =
-      svgTreeScopeResourcesFromElement(element());
-  treeScopeResources.removeResource(oldId);
-  treeScopeResources.updateResource(newId, this);
+  svgTreeScopeResourcesFromElement(element()).updateResource(oldId, newId,
+                                                             this);
 }
 
 void LayoutSVGResourceContainer::markAllClientsForInvalidation(