Create a new RenderFrameHost per child frame when --site-per-process is enabled.

content/browser/renderer_host/render_view_host_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 438 matching lines @@
   bool CanCommitURL(const GURL& url);
 
   // Checks that the given renderer can request |url|, if not it sets it to
   // about:blank.
   // empty_allowed must be set to false for navigations for security reasons.
   static void FilterURL(ChildProcessSecurityPolicyImpl* policy,
                         const RenderProcessHost* process,
                         bool empty_allowed,
                         GURL* url);
 
+  // Update the FrameTree with the new RenderFrameHost for the main frame.

[Charlie Reis, 2013/09/27 19:19:21]

This makes sense but is hard to read, since it's not clear where "the new" one
is coming from.  Perhaps:
Update the FrameTree to use this RenderViewHost's main frame RenderFrameHost.

nit: committed

[awong, 2013/09/27 20:50:09]

Done.

+  // Called when the RenderViewHost is commited.
+  //
+  // TODO(ajwong): Remove once RenderViewHost no longer owns the main frame
+  // RenderFrameHost.
+  void AttachToFrameTree();
+
   // NOTE: Do not add functions that just send an IPC message that are called in
   // one or two places. Have the caller send the IPC message directly (unless
   // the caller places are in different platforms, in which case it's better
   // to keep them consistent).
 
  protected:
   friend class RenderViewHostObserver;
 
   // Add and remove observers for filtering IPC messages.  Clients must be sure
   // to remove the observer before they go away.
@@ skipping 105 matching lines @@
   void OnRunFileChooser(const FileChooserParams& params);
   void OnDidAccessInitialDocument();
   void OnDomOperationResponse(const std::string& json_string,
                               int automation_id);
   void OnGetWindowSnapshot(const int snapshot_id);
 
 #if defined(OS_MACOSX) || defined(OS_ANDROID)
   void OnShowPopup(const ViewHostMsg_ShowPopup_Params& params);
 #endif
 
+  // TODO(nasko): Remove this accessor once RenderFrameHost moves into the frame
+  // tree.
+  RenderFrameHostImpl* main_render_frame_host() const {
+    return main_render_frame_host_.get();
+  }
+
  private:
   friend class TestRenderViewHost;
   FRIEND_TEST_ALL_PREFIXES(RenderViewHostTest, BasicRenderFrameHost);
   FRIEND_TEST_ALL_PREFIXES(RenderViewHostTest, RoutingIdSane);
 
-  // TODO(nasko): Remove this accessor once RenderFrameHost moves into the frame
-  // tree.
-  RenderFrameHostImpl* main_render_frame_host() const;
-
   // Sets whether this RenderViewHost is swapped out in favor of another,
   // and clears any waiting state that is no longer relevant.
   void SetSwappedOut(bool is_swapped_out);
 
   bool CanAccessFilesOfPageState(const PageState& state) const;
 
-  // This is an RenderFrameHost object associated with the top-level frame in
-  // the page rendered by this RenderViewHost.
-  // TODO(nasko): Remove this pointer once we have enough infrastructure to
-  // move this to the top-level FrameTreeNode.
+  // All RenderViewHosts must have a RenderFrameHost for its main frame.
+  // Currently the RenderFrameHost is created in lock step on construction
+  // and a pointer to the main frame is given to the FrameTreeNode
+  // when the RenderViewHost commits (see AttachToFrameTree()).
+  //
+  // TODO(ajwong): Make this reference non-owning. The root FrameTreeNode of
+  // the FrameTree should be responsible for owning the main frame's
+  // RenderFrameHost.
   scoped_ptr<RenderFrameHostImpl> main_render_frame_host_;
 
   // Our delegate, which wants to know about changes in the RenderView.
   RenderViewHostDelegate* delegate_;
 
   // The SiteInstance associated with this RenderViewHost.  All pages drawn
   // in this RenderViewHost are part of this SiteInstance.  Should not change
   // over time.
   scoped_refptr<SiteInstanceImpl> instance_;
 
@@ skipping 96 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostImpl);
 };
 
 #if defined(COMPILER_MSVC)
 #pragma warning(pop)
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_