Add ref-count on RenderViewHost for each new RenderFrameProxyHost.

content/browser/frame_host/frame_tree.h

Index: content/browser/frame_host/frame_tree.h
diff --git a/content/browser/frame_host/frame_tree.h b/content/browser/frame_host/frame_tree.h
index f5f1e51b31bcdf2b71beceae385beb97dd6452f8..53cba8bf49079ad92bcd52c445dc1d44a44fc2c4 100644
--- a/content/browser/frame_host/frame_tree.h
+++ b/content/browser/frame_host/frame_tree.h
@@ -122,10 +122,11 @@ class CONTENT_EXPORT FrameTree {
   // RenderFrameHost for each SiteInstance should be created before subframes.
   RenderViewHostImpl* GetRenderViewHost(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);
+  // Keeps track of which RenderFrameHosts and RenderFrameProxyHosts are using
+  // each RenderViewHost.  When the number drops to zero, we call Shutdown on
+  // the RenderViewHost.
+  void AddRenderViewHostRef(RenderViewHostImpl* render_view_host);
+  void ReleaseRenderViewHostRef(RenderViewHostImpl* render_view_host);
 
   // This is only meant to be called by FrameTreeNode. Triggers calling
   // the listener installed by SetFrameRemoveListener.