Give FrameTreeNodes a browser-global ID for use in navigation.

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 410 matching lines @@
 
   // User rotated the screen. Calls the "onorientationchange" Javascript hook.
   void SendOrientationChangeEvent(int orientation);
 
   // Sets a bit indicating whether the RenderView is responsible for displaying
   // a subframe in a different process from its parent page.
   void set_is_subframe(bool is_subframe) {
     is_subframe_ = is_subframe;
   }
 
+  // TODO(creis): Remove this when we replace frame IDs with RenderFrameHost
+  // routing IDs.
   int64 main_frame_id() const {
     return main_frame_id_;
   }
 
   // Set the opener to null in the renderer process.
   void DisownOpener();
 
   // Turn on accessibility testing. The given callback will be run
   // every time an accessibility notification is received from the
   // renderer process, and the accessibility tree it sent can be
@@ skipping 298 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_