Introduce RenderFrameProxyHost object and use it in RFHM.

content/browser/frame_host/render_frame_host_manager.h

Index: content/browser/frame_host/render_frame_host_manager.h
diff --git a/content/browser/frame_host/render_frame_host_manager.h b/content/browser/frame_host/render_frame_host_manager.h
index b06e2e32c7a15f5679847283df9140d510845231..a66b262a15a71990080f8d475006b6781634841b 100644
--- a/content/browser/frame_host/render_frame_host_manager.h
+++ b/content/browser/frame_host/render_frame_host_manager.h
@@ -30,6 +30,7 @@ class NavigationEntryImpl;
 class RenderFrameHostDelegate;
 class RenderFrameHostImpl;
 class RenderFrameHostManagerTest;
+class RenderFrameProxyHost;
 class RenderViewHost;
 class RenderViewHostImpl;
 class RenderWidgetHostDelegate;
@@ -268,9 +269,10 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
   bool IsOnSwappedOutList(RenderFrameHostImpl* rfh) const;
 
   // Returns the swapped out RenderViewHost or RenderFrameHost for the given
-  // SiteInstance, if any.
+  // SiteInstance, if any. This method is *deprecated* and
+  // GetRenderFrameProxyHost should be used.
   RenderViewHostImpl* GetSwappedOutRenderViewHost(SiteInstance* instance) const;
-  RenderFrameHostImpl* GetSwappedOutRenderFrameHost(
+  RenderFrameProxyHost* GetRenderFrameProxyHost(
       SiteInstance* instance) const;
 
   // Runs the unload handler in the current page, when we know that a pending
@@ -331,10 +333,10 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
     bool should_replace_current_entry;
   };
 
-  // Used with FrameTree::ForEach to erase inactive RenderFrameHosts from a
+  // Used with FrameTree::ForEach to erase RenderFrameProxyHosts from a
   // FrameTreeNode's RenderFrameHostManager.
-  static bool ClearSwappedOutRFHsInSiteInstance(int32 site_instance_id,
-                                                FrameTreeNode* node);
+  static bool ClearProxiesInSiteInstance(int32 site_instance_id,
+                                         FrameTreeNode* node);
 
   // Returns whether this tab should transition to a new renderer for
   // cross-site URLs.  Enabled unless we see the --process-per-tab command line
@@ -367,11 +369,11 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
       bool force_browsing_instance_swap);
 
   // Creates a RenderFrameHost and corresponding RenderViewHost if necessary.
-  RenderFrameHostImpl* CreateRenderFrameHost(SiteInstance* instance,
-                                             int view_routing_id,
-                                             int frame_routing_id,
-                                             bool swapped_out,
-                                             bool hidden);
+  scoped_ptr<RenderFrameHostImpl> CreateRenderFrameHost(SiteInstance* instance,
+                                                        int view_routing_id,
+                                                        int frame_routing_id,
+                                                        bool swapped_out,
+                                                        bool hidden);
 
   // Sets up the necessary state for a new RenderViewHost with the given opener,
   // if necessary.  Returns early if the RenderViewHost has already been
@@ -447,10 +449,9 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
   scoped_ptr<WebUIImpl> pending_web_ui_;
   base::WeakPtr<WebUIImpl> pending_and_current_web_ui_;
 
-  // A map of site instance ID to swapped out RenderFrameHosts.  This may
-  // include pending_render_frame_host_ for navigations to existing entries.
-  typedef base::hash_map<int32, RenderFrameHostImpl*> RenderFrameHostMap;
-  RenderFrameHostMap swapped_out_hosts_;
+  // A map of site instance ID to RenderFrameProxyHosts.

[Charlie Reis, 2014/04/09 21:48:30]

I'm actually not sure whether the pending RFH is ever in this map or not.  For
example, see my question in CommitPending.

Can you give me an overview of how this case (navigations to existing entries)
has changed?

[nasko, 2014/04/10 20:37:36]

Pending is no longer in that map. It is removed if found in the map and set as
the pending, then returned to the map on cancelling navigation if the
SiteInstance is being used by others.

+  typedef base::hash_map<int32, RenderFrameProxyHost*> RenderFrameHostMap;

[Charlie Reis, 2014/04/09 21:48:30]

nit: We should probably call this RenderFrameProxyHostMap now.

[nasko, 2014/04/10 20:37:36]

Done.

+  RenderFrameHostMap proxy_hosts_;
 
   // A map of RenderFrameHosts pending shutdown.
   typedef base::hash_map<int32, linked_ptr<RenderFrameHostImpl> >