Make RenderFrameHostManager swap RenderFrameHosts, not RenderViewHosts.

content/browser/frame_host/frame_tree.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_FRAME_TREE_H_
 #define CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 35 matching lines @@
   // RenderFrameHostManagers.
   // TODO(creis): This set of delegates will change as we move things to
   // Navigator.
   FrameTree(Navigator* navigator,
             RenderFrameHostDelegate* render_frame_delegate,
             RenderViewHostDelegate* render_view_delegate,
             RenderWidgetHostDelegate* render_widget_delegate,
             RenderFrameHostManager::Delegate* manager_delegate);
   ~FrameTree();
 
+  FrameTreeNode* root() const { return root_.get(); }
+
   // Returns the FrameTreeNode with the given |frame_tree_node_id|.
   FrameTreeNode* FindByID(int64 frame_tree_node_id);
 
   // Executes |on_node| on each node in the frame tree.  If |on_node| returns
   // false, terminates the iteration immediately. Returning false is useful
   // if |on_node| is just doing a search over the tree.
   void ForEach(const base::Callback<bool(FrameTreeNode*)>& on_node) const;
 
   // After the FrameTree is created, or after SwapMainFrame() has been called,
   // the root node does not yet have a frame id. This is allocated by the
   // renderer and is published to the browser process on the first navigation
   // after a swap. These two functions are used to set the root node's frame
   // id.
   //
   // TODO(ajwong): Remove these once RenderFrameHost's routing id replaces
   // frame_id.
   bool IsFirstNavigationAfterSwap() const;
   void OnFirstNavigationAfterSwap(int main_frame_id);
 
   // Frame tree manipulation routines.
   // TODO(creis): These should take in RenderFrameHost routing IDs.
-  RenderFrameHostImpl* AddFrame(int render_frame_host_id,
+  RenderFrameHostImpl* AddFrame(int frame_routing_id,
                                 int64 parent_frame_tree_node_id,
                                 int64 frame_id,
                                 const std::string& frame_name);
   void RemoveFrame(RenderFrameHostImpl* render_frame_host,
                    int64 parent_frame_id,
                    int64 frame_id);
   void SetFrameUrl(int64 frame_id, const GURL& url);
 
-  // Resets the FrameTree and changes RenderFrameHost for the main frame.
+  // Clears process specific-state after a main frame process swap.
   // This destroys most of the frame tree but retains the root node so that
   // navigation state may be kept on it between process swaps. Used to
   // support bookkeeping for top-level navigations.
-  //
-  // If |main_frame| is NULL, reset tree to initially constructed state.
-  //
-  // TODO(ajwong): This function should not be given a |main_frame|. This is
-  // required currently because the RenderViewHost owns its main frame. When
-  // that relation is fixed, the FrameTree should be responsible for
-  // created/destroying the main frame on the swap.
-  void SwapMainFrame(RenderFrameHostImpl* main_frame);
+  // TODO(creis): Look into how we can remove the need for this method.
+  void ResetForMainFrameSwap();
 
   // Convenience accessor for the main frame's RenderFrameHostImpl.
   RenderFrameHostImpl* GetMainFrame() const;
 
   // Allows a client to listen for frame removal.  The listener should expect
   // to receive the RenderViewHostImpl containing the frame and the renderer-
   // specific frame ID of the removed frame.
   // TODO(creis): These parameters will later change to be the RenderFrameHost.
   void SetFrameRemoveListener(
       const base::Callback<void(RenderViewHostImpl*, int64)>& on_frame_removed);
 
-  FrameTreeNode* root() const { return root_.get(); }
+  void ClearFrameRemoveListenerForTesting();
+
+  // Creates a RenderViewHost for a new main frame RenderFrameHost in the given
+  // |site_instance|.  The RenderViewHost will have its Shutdown method called
+  // when all of the RenderFrameHosts using it are deleted.
+  RenderViewHostImpl* CreateRenderViewHostForMainFrame(
+      SiteInstance* site_instance,
+      int routing_id,
+      int main_frame_routing_id,
+      bool swapped_out,
+      bool hidden);
+
+  // Returns the existing RenderViewHost for a new subframe RenderFrameHost.
+  // There should always be such a RenderViewHost, because the main frame
+  // RenderFrameHost for each SiteInstance should be created before subframes.
+  RenderViewHostImpl* GetRenderViewHostForSubFrame(SiteInstance* site_instance);
+
+  // Keeps track of which RenderFrameHosts are using each RenderViewHost.  When
+  // the number drops to zero, we call Shutdown on the RenderViewHost.
+  void RegisterRenderFrameHost(RenderFrameHostImpl* render_frame_host);
+  void UnregisterRenderFrameHost(RenderFrameHostImpl* render_frame_host);
 
  private:
+  typedef std::pair<RenderViewHostImpl*, int> RenderViewHostRefCount;
+  typedef base::hash_map<int, RenderViewHostRefCount> RenderViewHostMap;
+
   // Returns the FrameTreeNode with the given renderer-specific |frame_id|.
   // For internal use only.
   // TODO(creis): Replace this with a version that takes in a routing ID.
   FrameTreeNode* FindByFrameID(int64 frame_id);
 
-  scoped_ptr<FrameTreeNode> CreateNode(int64 frame_id,
-                                       const std::string& frame_name,
-                                       int render_frame_host_id,
-                                       FrameTreeNode* parent_node);
-
   // These delegates are installed into all the RenderViewHosts and
   // RenderFrameHosts that we create.
   RenderFrameHostDelegate* render_frame_delegate_;
   RenderViewHostDelegate* render_view_delegate_;
   RenderWidgetHostDelegate* render_widget_delegate_;
   RenderFrameHostManager::Delegate* manager_delegate_;
 
+  // Map of SiteInstance ID to a (RenderViewHost, refcount) pair.  This allows
+  // us to look up the RenderViewHost for a given SiteInstance when creating
+  // RenderFrameHosts, and it allows us to call Shutdown on the RenderViewHost
+  // and remove it from the map when no more RenderFrameHosts are using it.
+  //
+  // Must be declared before |root_| so that it is deleted afterward.  Otherwise
+  // the map will be cleared before we delete the RenderFrameHosts in the tree.
+  RenderViewHostMap render_view_host_map_;
+
   scoped_ptr<FrameTreeNode> root_;
 
   base::Callback<void(RenderViewHostImpl*, int64)> on_frame_removed_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameTree);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_H_