Give the main frame a RenderWidget.

chrome/browser/ui/browser.cc

Index: chrome/browser/ui/browser.cc
diff --git a/chrome/browser/ui/browser.cc b/chrome/browser/ui/browser.cc
index 5ad781c63e1c0d52ad5d5abeda232e7c3ee7c987..9af98ed97e0d4ac1698be56cc66c96b0770189fd 100644
--- a/chrome/browser/ui/browser.cc
+++ b/chrome/browser/ui/browser.cc
@@ -1630,8 +1630,10 @@ void Browser::ShowRepostFormWarningDialog(WebContents* source) {
 
 bool Browser::ShouldCreateWebContents(
     WebContents* web_contents,
-    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,
     WindowContainerType window_container_type,
     const std::string& frame_name,
     const GURL& target_url,
@@ -1639,13 +1641,10 @@ bool Browser::ShouldCreateWebContents(
     content::SessionStorageNamespace* session_storage_namespace) {
   if (window_container_type == WINDOW_CONTAINER_TYPE_BACKGROUND) {
     // If a BackgroundContents is created, suppress the normal WebContents.
-    return !MaybeCreateBackgroundContents(route_id,
-                                          main_frame_route_id,
-                                          web_contents,
-                                          frame_name,
-                                          target_url,
-                                          partition_id,
-                                          session_storage_namespace);
+    return !MaybeCreateBackgroundContents(
+        route_id, main_frame_route_id, main_frame_widget_route_id, surface_id,
+        web_contents, frame_name, target_url, partition_id,
+        session_storage_namespace);
   }
 
   return true;
@@ -2567,8 +2566,10 @@ bool Browser::ShouldHideUIForFullscreen() const {
 }
 
 bool Browser::MaybeCreateBackgroundContents(
-    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,
     WebContents* opener_web_contents,
     const std::string& frame_name,
     const GURL& target_url,
@@ -2631,15 +2632,11 @@ bool Browser::MaybeCreateBackgroundContents(
       content::SiteInstance::Create(opener_web_contents->GetBrowserContext());
 
   // Passed all the checks, so this should be created as a BackgroundContents.
-  BackgroundContents* contents =
-      service->CreateBackgroundContents(site_instance.get(),
-                                        route_id,
-                                        main_frame_route_id,
-                                        profile_,
-                                        frame_name,
-                                        base::ASCIIToUTF16(extension->id()),
-                                        partition_id,
-                                        session_storage_namespace);
+  BackgroundContents* contents = service->CreateBackgroundContents(
+      site_instance.get(), route_id, main_frame_route_id,
+      main_frame_widget_route_id, surface_id, profile_, frame_name,
+      base::ASCIIToUTF16(extension->id()), partition_id,
+      session_storage_namespace);
 
   // When a separate process is used, the original renderer cannot access the
   // new window later, thus we need to navigate the window now.