Move SwapOut methods to RenderFrameHost.

content/browser/frame_host/render_frame_host_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_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 107 matching lines @@
   // handler and determine whether a transfer to a different RenderFrameHost is
   // needed.
   void OnCrossSiteResponse(
       const GlobalRequestID& global_request_id,
       scoped_ptr<CrossSiteTransferringRequest> cross_site_transferring_request,
       const std::vector<GURL>& transfer_url_chain,
       const Referrer& referrer,
       PageTransition page_transition,
       bool should_replace_current_entry);
 
-  // Hack to get this subframe to swap out, without yet moving over all the
-  // SwapOut state and machinery from RenderViewHost.
+  // Tells the renderer that this RenderFrame is being swapped out for one in a
+  // different renderer process.  It should run its unload handler and move to
+  // a blank document.  The renderer should preserve the Frame object until it
+  // exits, in case we come back.  The renderer can exit if it has no other
+  // active RenderFrames, but not until WasSwappedOut is called (when it is no
+  // longer visible).
   void SwapOut();
+
   void OnSwappedOut(bool timed_out);
   bool is_swapped_out() { return is_swapped_out_; }
   void set_swapped_out(bool is_swapped_out) {
     is_swapped_out_ = is_swapped_out;
   }
 
   // Sets the RVH for |this| as pending shutdown. |on_swap_out| will be called
   // when the SwapOutACK is received.
   void SetPendingShutdown(const base::Closure& on_swap_out);
 
@@ skipping 102 matching lines @@
 
   // When the last BeforeUnload message was sent.
   base::TimeTicks send_before_unload_start_time_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_