Fix up that no render SVG shape when change clip-path to visible after hidden.

third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceContainer.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 67 matching lines @@
 
   LayoutSVGHiddenContainer::willBeDestroyed();
   if (m_registered)
     svgExtensionsFromElement(element()).removeResource(m_id);
 }
 
 void LayoutSVGResourceContainer::styleDidChange(StyleDifference diff,
                                                 const ComputedStyle* oldStyle) {
   LayoutSVGHiddenContainer::styleDidChange(diff, oldStyle);
 
+  for (auto* client : m_clients) {
+    // Check whether delete the old resource or not for client that is NoChange.
+    // If ResourceContainer is visible, client is visible, width and height
+    // are '0', the old cache should be removed and set pending resource.
+    LayoutRect boundingBox = client->visualRect();
+    if (style()->visibility() == EVisibility::Visible &&

[fs, 2017/01/05 17:01:47]

I think this may be starting to approach the right track, but not quite there
yet. The 'visibility' on the LayoutSVGResourceContainer itself (<clipPath>,
<mask> and <pattern> I think are the relevant ones here) does not actually have
any influence on the actual "content". So, I'd expect the invalidation to take
place through the children of the LayoutSVGResourceContainer (probably via
SVGResourceCache::clientStyleChanged?)

+        client->style()->visibility() == EVisibility::Visible &&
+        !boundingBox.width() && !boundingBox.height())
+    {
+      SVGResources* resources =
+          SVGResourcesCache::cachedResourcesForLayoutObject(client);
+      if (resources) {
+        // Remove the old resource.

[fs, 2017/01/05 17:01:47]

This looks too heavy-handed, if you wanted to invalidate clients,
removeAllClientsFromCache would probably be better. (If you want to be
selective, removeClientFromCache.) You should also not be
unregistering/re-registering the resource.

+        resources->resourceDestroyed(this);
+        Element* clientElement = toElement(client->node());
+         svgExtensionsFromElement(clientElement)
+          .addPendingResource(m_id, clientElement);
+        m_registered = false;
+      }
+    }
+  }
+
   if (!m_registered) {
     m_registered = true;
     registerResource();
   }
 }
 
 void LayoutSVGResourceContainer::detachAllClients() {
   for (auto* client : m_clients) {
     // Unlink the resource from the client's SVGResources. (The actual
     // removal will be signaled after processing all the clients.)
@@ skipping 212 matching lines @@
       // This will process the rest of the ancestors.
       toLayoutSVGResourceContainer(current)->removeAllClientsFromCache();
       break;
     }
 
     current = current->parent();
   }
 }
 
 }  // namespace blink