Do not create proxy hosts in the subtree of navigating frame.

content/browser/frame_host/frame_tree.cc

Index: content/browser/frame_host/frame_tree.cc
diff --git a/content/browser/frame_host/frame_tree.cc b/content/browser/frame_host/frame_tree.cc
index de6c69b59bd06e46c839dbcff6e67ef7012d55b7..e22e720f171bdca144f5708feecb1dc7f98bc898 100644
--- a/content/browser/frame_host/frame_tree.cc
+++ b/content/browser/frame_host/frame_tree.cc
@@ -65,13 +65,8 @@ bool ResetNodesForNewProcess(RenderViewHost* render_view_host,
   return true;
 }
 
-bool CreateProxyForSiteInstance(FrameTreeNode* source_node,
-                                const scoped_refptr<SiteInstance>& instance,
+bool CreateProxyForSiteInstance(const scoped_refptr<SiteInstance>& instance,
                                 FrameTreeNode* node) {
-  // Skip the node that initiated the creation.
-  if (source_node == node)
-    return true;
-
   node->render_manager()->CreateRenderFrameProxy(instance.get());
   return true;
 }
@@ -142,6 +137,26 @@ void FrameTree::ForEach(
   }
 }
 
+void FrameTree::ForEach(
+    const base::Callback<bool(FrameTreeNode*)>& on_node,
+    FrameTreeNode* skip_node) const {
+  std::queue<FrameTreeNode*> queue;
+  queue.push(root_.get());
+
+  while (!queue.empty()) {
+    FrameTreeNode* node = queue.front();
+    queue.pop();
+    if (skip_node == node)
+      continue;
+
+    if (!on_node.Run(node))
+      break;
+
+    for (size_t i = 0; i < node->child_count(); ++i)
+      queue.push(node->child_at(i));
+  }
+}
+
 RenderFrameHostImpl* FrameTree::AddFrame(FrameTreeNode* parent,
                                          int new_routing_id,
                                          const std::string& frame_name) {
@@ -193,7 +208,12 @@ void FrameTree::CreateProxiesForSiteInstance(
   }
 
   scoped_refptr<SiteInstance> instance(site_instance);
-  ForEach(base::Bind(&CreateProxyForSiteInstance, source, instance));
+
+  // When creating proxies in the FrameTree, it is in reponse to a node

[awong, 2014/09/03 21:58:38]

"Proxies are created in the FrameTree in response to a node navigating to a new
SiteInstance."

[nasko, 2014/09/03 23:50:19]

Done.

+  // navigating to a new SiteInstance. Since that node's navigation will replace

[awong, 2014/09/03 21:58:38]

"this nodes" -> |source|'s

[nasko, 2014/09/03 23:50:19]

Done.

+  // the currently loaded document, the entire subtree under the node will be

[awong, 2014/09/03 21:58:38]

the node -> |source|

[nasko, 2014/09/03 23:50:19]

Done.

+  // removed.
+  ForEach(base::Bind(&CreateProxyForSiteInstance, instance), source);
 }
 
 void FrameTree::ResetForMainFrameSwap() {