Make RenderFrame(Host) own a RenderWidget(Host).

content/renderer/render_frame_impl.h

Index: content/renderer/render_frame_impl.h
diff --git a/content/renderer/render_frame_impl.h b/content/renderer/render_frame_impl.h
index 2413312f06c12063b7430d8a3bbccadf16ebc09d..34808f79f7a882f030ae3513ed67bc9037ee2170 100644
--- a/content/renderer/render_frame_impl.h
+++ b/content/renderer/render_frame_impl.h
@@ -43,6 +43,7 @@ class GURL;
 class TransportDIB;
 struct FrameHostMsg_AddNavigationTransitionData_Params;
 struct FrameMsg_Navigate_Params;
+struct FrameMsg_NewFrame_WidgetParams;
 struct FrameMsg_RequestNavigation_Params;
 
 namespace blink {
@@ -71,6 +72,7 @@ class WebEncryptedMediaClientImpl;
 namespace content {
 
 class ChildFrameCompositingHelper;
+class CompositorDependencies;
 class ExternalPopupMenu;
 class GeolocationDispatcher;
 class ManifestManager;
@@ -122,7 +124,9 @@ class CONTENT_EXPORT RenderFrameImpl
   // through Blink and Create.
   static void CreateFrame(int routing_id,
                           int parent_routing_id,
-                          int proxy_routing_id);
+                          int proxy_routing_id,
+                          CompositorDependencies* compositor_deps,
+                          const FrameMsg_NewFrame_WidgetParams& params);
 
   // Returns the RenderFrameImpl for the given routing ID.
   static RenderFrameImpl* FromRoutingID(int routing_id);
@@ -725,6 +729,13 @@ class CONTENT_EXPORT RenderFrameImpl
   // TODO(creis): Remove this after switching to PlzNavigate.
   int proxy_routing_id_;
 
+  // Used when the RenderFrame is a local root. For now, RenderWidgets are
+  // added only when a child frame is in a different process from its parent
+  // frame, but eventually this will also apply to top-level frames.
+  // TODO(kenrb): Correct the above statement when top-level frames have their
+  // own RenderWidgets.
+  scoped_refptr<RenderWidget> render_widget_;
+
 #if defined(ENABLE_PLUGINS)
   // Current text input composition text. Empty if no composition is in
   // progress.