Send a subtree of same-process PageStates for back/forward child frames.

content/renderer/render_frame_impl.h

 // Copyright 2013 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_RENDERER_RENDER_FRAME_IMPL_H_
 #define CONTENT_RENDERER_RENDER_FRAME_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1107 matching lines @@
   // Non-null when the RenderFrame is a local root for compositing, input,
   // layout, etc. A local frame is also a local root iff it does not have a
   // parent that is a local frame.
   scoped_refptr<RenderWidget> render_widget_;
 
   // Temporarily holds state pertaining to a navigation that has been initiated
   // until the NavigationState corresponding to the new navigation is created in
   // didCreateDataSource().
   std::unique_ptr<NavigationParams> pending_navigation_params_;
 
-  // Keeps track of which future subframes the browser process has history items
-  // for during a history navigation, as well as whether those items are for
-  // about:blank.  The renderer process should ask the browser for history items
-  // when subframes with these names are created (as long as they are not
-  // staying at about:blank), and directly load the initial URLs for any other
-  // subframes.
-  //
-  // This state is incrementally cleared as it is used and then reset in
-  // didStopLoading, since it is not needed after the first load completes and
-  // is never used after the initial navigation.
-  // TODO(creis): Expand this to include any corresponding same-process
-  // PageStates for the whole subtree in https://crbug.com/639842.
-  std::map<std::string, bool> history_subframe_unique_names_;
-
   // Stores the current history item for this frame, so that updates to it can
   // be reported to the browser process via SendUpdateState.
   blink::WebHistoryItem current_history_item_;
 
 #if BUILDFLAG(ENABLE_PLUGINS)
   // Current text input composition text. Empty if no composition is in
   // progress.
   base::string16 pepper_composition_text_;
 
   PluginPowerSaverHelper* plugin_power_saver_helper_;
@@ skipping 193 matching lines @@
   bool browser_side_navigation_pending_ = false;
 
   base::WeakPtrFactory<RenderFrameImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_FRAME_IMPL_H_