Revert of 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 d5a183ff8cbdb3d1ddd04bbc11c38b092f834a50..3415e46780ea6f1145fe1968a2f107a6f842be5c 100644
--- a/content/browser/frame_host/frame_tree.cc
+++ b/content/browser/frame_host/frame_tree.cc
@@ -52,8 +52,13 @@
   return true;
 }
 
-bool CreateProxyForSiteInstance(const scoped_refptr<SiteInstance>& instance,
+bool CreateProxyForSiteInstance(FrameTreeNode* source_node,
+                                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;
 }
@@ -123,21 +128,12 @@
 
 void FrameTree::ForEach(
     const base::Callback<bool(FrameTreeNode*)>& on_node) const {
-  ForEach(on_node, NULL);
-}
-
-void FrameTree::ForEach(
-    const base::Callback<bool(FrameTreeNode*)>& on_node,
-    FrameTreeNode* skip_this_subtree) const {
   std::queue<FrameTreeNode*> queue;
   queue.push(root_.get());
 
   while (!queue.empty()) {
     FrameTreeNode* node = queue.front();
     queue.pop();
-    if (skip_this_subtree == node)
-      continue;
-
     if (!on_node.Run(node))
       break;
 
@@ -197,11 +193,7 @@
   }
 
   scoped_refptr<SiteInstance> instance(site_instance);
-
-  // Proxies are created in the FrameTree in response to a node navigating to a
-  // new SiteInstance. Since |source|'s navigation will replace the currently
-  // loaded document, the entire subtree under |source| will be removed.
-  ForEach(base::Bind(&CreateProxyForSiteInstance, instance), source);
+  ForEach(base::Bind(&CreateProxyForSiteInstance, source, instance));
 }
 
 void FrameTree::ResetForMainFrameSwap() {