Adding RenderWidgetHostViewChildFrame for OOPIF view.

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index e12d07a8e3ea6193f5b8e534737161b679327875..481b7cddd52dc1a1feaa4ab362f3ff681bb2aaf2 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -19,6 +19,7 @@ class FilePath;
 
 namespace content {
 
+class CrossProcessFrameConnector;
 class FrameTree;
 class FrameTreeNode;
 class RenderFrameHostDelegate;
@@ -51,6 +52,18 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
   RenderViewHostImpl* render_view_host() { return render_view_host_; }
   RenderFrameHostDelegate* delegate() { return delegate_; }
 
+  // This function is called when this is a swapped out RenderFrameHost that

[Charlie Reis, 2013/12/20 00:24:22]

"when this is a swapped out RenderFrameHost:" That's a temporary state.  Does
this need to be called with NULL if this RenderFrameHost becomes active again?

+  // lives in the same process as the parent frame. The
+  // |cross_process_frame_connector| allows the non-swapped-out

[Charlie Reis, 2013/12/20 00:24:22]

nit: non-swapped-out -> active

+  // RenderFrameHost for a frame to communicate with the parent process
+  // so that it may composite drawing data.
+  //
+  // Ownership is not transfered.
+  void set_cross_process_frame_connector(
+      CrossProcessFrameConnector* cross_process_frame_connector) {
+    cross_process_frame_connector_ = cross_process_frame_connector;
+  }
+
  protected:
   friend class RenderFrameHostFactory;
 
@@ -86,6 +99,18 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
 
   RenderFrameHostDelegate* delegate_;
 
+  // |cross_process_frame_connector_| passes messages from an out-of-process
+  // child frame to the parent process for compositing.
+  //
+  // This is only non-NULL when this is the swapped out RenderFrameHost in
+  // the same site instance as this frame's parent.

[Charlie Reis, 2013/12/20 00:24:22]

nit: SiteInstance

+  //
+  // See the class comment above CrossProcessFrameConnector for more
+  // information.
+  //
+  // This will move to RenderFrameProxyHost when that class is created.
+  CrossProcessFrameConnector* cross_process_frame_connector_;
+
   // Reference to the whole frame tree that this RenderFrameHost belongs too.
   // Allows this RenderFrameHost to add and remove nodes in response to
   // messages from the renderer requesting DOM manipulation.