Create RenderFrameProxyHost at time of swap-out instead of commit.

content/browser/frame_host/render_frame_proxy_host.h

 // Copyright 2014 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_PROXY_HOST_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/site_instance_impl.h"
+#include "ipc/ipc_listener.h"
+#include "ipc/ipc_sender.h"
 
+class FrameTreeNode;
 class RenderProcessHost;
 class RenderFrameHostImpl;
 class RenderViewHostImpl;
 
 namespace content {
 
 // When a page's frames are rendered by multiple processes, each renderer has a
 // full copy of the frame tree. It has full RenderFrames for the frames it is
 // responsible for rendering and placeholder objects (i.e., RenderFrameProxies)
 // for frames rendered by other processes.
 //
 // This class is the browser-side host object for the placeholder. Each node in
 // the frame tree has a RenderFrameHost for the active SiteInstance and a set
 // of RenderFrameProxyHost objects - one for all other SiteInstances with
 // references to this frame. The proxies allow us to keep existing window
 // references valid over cross-process navigations and route cross-site
 // asynchronous JavaScript calls, such as postMessage.
 //
 // For now, RenderFrameProxyHost is created when a RenderFrameHost is swapped
-// out and acts just as a wrapper. If a RenderFrameHost can be deleted, no
-// proxy object is created. It is destroyed when the RenderFrameHost is swapped
-// back in or is no longer referenced and is therefore deleted.
+// out and acts just as a wrapper. It is destroyed when the RenderFrameHost is
+// swapped back in or is no longer referenced and is therefore deleted.
 //
 // Long term, RenderFrameProxyHost will be created whenever a cross-site
 // navigation occurs and a reference to the frame navigating needs to be kept
 // alive. A RenderFrameProxyHost and a RenderFrameHost for the same SiteInstance
 // can exist at the same time, but only one will be "active" at a time.
 // There are two cases where the two objects will coexist:
 // * When navigating cross-process and there is already a RenderFrameProxyHost
 // for the new SiteInstance. A pending RenderFrameHost is created, but it is
 // not used until it commits. At that point, RenderFrameHostManager transitions
 // the pending RenderFrameHost to the active one and deletes the proxy.
 // * When navigating cross-process and the existing document has an unload
 // event handler. When the new navigation commits, RenderFrameHostManager
 // creates a RenderFrameProxyHost for the old SiteInstance and uses it going
 // forward. It also instructs the RenderFrameHost to run the unload event
 // handler and is kept alive for the duration. Once the event handling is
 // complete, the RenderFrameHost is deleted.
-class RenderFrameProxyHost {
+class RenderFrameProxyHost
+    : public IPC::Listener,
+      public IPC::Sender {
  public:
-  explicit RenderFrameProxyHost(
-       scoped_ptr<RenderFrameHostImpl> render_frame_host);
-  ~RenderFrameProxyHost();
+  RenderFrameProxyHost(SiteInstance* site_instance,
+                       FrameTreeNode* frame_tree_node);
+  virtual ~RenderFrameProxyHost();
 
   RenderProcessHost* GetProcess() {
-    return render_frame_host_->GetProcess();
+    return site_instance_->GetProcess();
+  }
+
+  int GetRoutingID() {
+    return routing_id_;
   }
 
   SiteInstance* GetSiteInstance() {
     return site_instance_.get();
   }
 
-  // TODO(nasko): The following methods should be removed when swapping out
-  // of RenderFrameHosts is no longer used.
+  // TODO(nasko): The following methods should be removed once we don't have a
+  // swapped out state on RenderFrameHosts. See https://crbug.com/357747.
   RenderFrameHostImpl* render_frame_host() {
     return render_frame_host_.get();
   }
   RenderViewHostImpl* render_view_host() {
     return render_frame_host_->render_view_host();
   }
-  scoped_ptr<RenderFrameHostImpl> PassFrameHost() {
-    return render_frame_host_.Pass();
+  void TakeFrameHostOwnership(
+      scoped_ptr<RenderFrameHostImpl> render_frame_host) {
+    render_frame_host_ = render_frame_host.Pass();
   }
+  scoped_ptr<RenderFrameHostImpl> PassFrameHostOwnership();
+
+  // IPC::Sender
+  virtual bool Send(IPC::Message* msg) OVERRIDE;
 
  private:
+  // IPC::Listener
+  virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
+
+  // This RenderFrameProxyHost's routing id.
+  int routing_id_;
+
+  // The SiteInstance this proxy is associated with.
   scoped_refptr<SiteInstance> site_instance_;
 
-  // TODO(nasko): For now, hide the RenderFrameHost inside the proxy, but remove
-  // it once we have all the code support for proper proxy objects.
+  // The node in the frame tree where this proxy is located.
+  FrameTreeNode* frame_tree_node_;
+
+  // TODO(nasko): This can be removed once we don't have a swapped out state on
+  // RenderFrameHosts. See https://crbug.com/357747.
   scoped_ptr<RenderFrameHostImpl> render_frame_host_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameProxyHost);
 };
 
 }  // namespace
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_PROXY_HOST_H_