Give the main frame a RenderWidget.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 19033a8ecdfa24d7156bc34187e4d0aa82ada488..f406aabc34fa567f13a2d6e7aa8230ae79053da8 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -314,8 +314,16 @@ bool RenderViewHostImpl::CreateRenderView(
 #endif
   params.web_preferences = GetWebkitPreferences();
   params.view_id = GetRoutingID();
+  params.view_surface_id = surface_id();
   params.main_frame_routing_id = main_frame_routing_id_;
-  params.surface_id = surface_id();
+  if (main_frame_routing_id_ != MSG_ROUTING_NONE) {
+    RenderFrameHostImpl* main_rfh = RenderFrameHostImpl::FromID(
+        GetProcess()->GetID(), main_frame_routing_id_);
+    DCHECK(main_rfh);
+    RenderWidgetHostImpl* main_rwh = main_rfh->GetRenderWidgetHostForFrame();
+    params.main_frame_widget_routing_id = main_rwh->GetRoutingID();
+    params.widget_surface_id = main_rwh->surface_id();
+  }
   params.session_storage_namespace_id =
       delegate_->GetSessionStorageNamespace(instance_.get())->id();
   // Ensure the RenderView sets its opener correctly.
@@ -750,7 +758,9 @@ void RenderViewHostImpl::AllowBindings(int bindings_flags) {
     // This process has no bindings yet. Make sure it does not have more
     // than this single active view.
     // --single-process only has one renderer.
-    if (GetProcess()->GetActiveViewCount() > 1 &&
+    // TODO(dcheng): IMPORTANT IMPORTANT IMPORTANT. Once RenderViewHost is no
+    // longer a RenderWidgetHost, this *must* be decremented back to 1.
+    if (GetProcess()->GetActiveViewCount() > 2 &&
         !base::CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kSingleProcess))
       return;
@@ -984,8 +994,10 @@ bool RenderViewHostImpl::IsRenderView() const {
 }
 
 void RenderViewHostImpl::CreateNewWindow(
-    int route_id,
-    int main_frame_route_id,
+    int32 route_id,
+    int32 main_frame_route_id,
+    int32 main_frame_widget_route_id,
+    int32 surface_id,
     const ViewHostMsg_CreateWindow_Params& params,
     SessionStorageNamespace* session_storage_namespace) {
   ViewHostMsg_CreateWindow_Params validated_params(params);
@@ -994,6 +1006,7 @@ void RenderViewHostImpl::CreateNewWindow(
   GetProcess()->FilterURL(true, &validated_params.opener_security_origin);
 
   delegate_->CreateNewWindow(GetSiteInstance(), route_id, main_frame_route_id,
+                             main_frame_widget_route_id, surface_id,
                              validated_params, session_storage_namespace);
 }