Give the main frame a RenderWidget.

content/public/test/mock_render_thread.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/public/test/mock_render_thread.h"
 
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "content/common/frame_messages.h"
 #include "content/common/view_messages.h"
@@ skipping 197 matching lines @@
                                       int* route_id,
                                       int* surface_id) {
   opener_id_ = opener_id;
   *route_id = routing_id_;
   *surface_id = surface_id_;
 }
 
 // The View expects to be returned a valid route_id different from its own.
 void MockRenderThread::OnCreateWindow(
     const ViewHostMsg_CreateWindow_Params& params,
-    int* route_id,
-    int* main_frame_route_id,
-    int* surface_id,
-    int64* cloned_session_storage_namespace_id) {
-  *route_id = new_window_routing_id_;
-  *main_frame_route_id = new_window_main_frame_routing_id_;
-  *surface_id = surface_id_;
-  *cloned_session_storage_namespace_id = 0;
+    ViewHostMsg_CreateWindow_Reply* reply) {
+  reply->route_id = new_window_routing_id_;
+  reply->main_frame_route_id = new_window_main_frame_routing_id_;
+  // TODO(dcheng): Set main_frame_widget_route_id too??

[ncarter (slow), 2015/08/24 20:55:35]

You ought to at least set it to something, I think.
|new_window_main_frame_routing_id_| is always zero, fwiw.

[dcheng, 2015/09/03 16:33:09]

Done.

+  reply->surface_id = surface_id_;
+  reply->cloned_session_storage_namespace_id = 0;
 }
 
 // The Frame expects to be returned a valid route_id different from its own.
 void MockRenderThread::OnCreateChildFrame(int new_frame_routing_id,
                                           blink::WebTreeScopeType scope,
                                           const std::string& frame_name,
                                           blink::WebSandboxFlags sandbox_flags,
                                           int* new_render_frame_id) {
   *new_render_frame_id = new_frame_routing_id_++;
 }
@@ skipping 26 matching lines @@
 void MockRenderThread::OnDuplicateSection(
     base::SharedMemoryHandle renderer_handle,
     base::SharedMemoryHandle* browser_handle) {
   // We don't have to duplicate the input handles since RenderViewTest does not
   // separate a browser process from a renderer process.
   *browser_handle = renderer_handle;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace content