RenderWidget popup should be a NSWindow so it can go outside the main window.

content/browser/renderer_host/test_render_view_host.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_TEST_RENDER_VIEW_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_TEST_RENDER_VIEW_HOST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 64 matching lines @@
   virtual bool IsSpeaking() const OVERRIDE;
   virtual void StopSpeaking() OVERRIDE;
 #endif  // defined(OS_MACOSX)
 #if defined(TOOLKIT_GTK)
   virtual GdkEventButton* GetLastMouseDown() OVERRIDE;
   virtual gfx::NativeView BuildInputMethodsGtkMenu() OVERRIDE;
 #endif  // defined(TOOLKIT_GTK)
 
   // RenderWidgetHostViewPort implementation.
   virtual void InitAsPopup(RenderWidgetHostView* parent_host_view,
-                           const gfx::Rect& pos) OVERRIDE {}
+                           const gfx::Rect& pos,
+                           gfx::NativeWindow popup_window = NULL) OVERRIDE {}
   virtual void InitAsFullscreen(
       RenderWidgetHostView* reference_host_view) OVERRIDE {}
   virtual void WasShown() OVERRIDE {}
   virtual void WasHidden() OVERRIDE {}
   virtual void MovePluginWindows(
       const gfx::Vector2d& scroll_offset,
       const std::vector<webkit::npapi::WebPluginGeometry>& moves) OVERRIDE {}
   virtual void Focus() OVERRIDE {}
   virtual void Blur() OVERRIDE {}
   virtual void SetIsLoading(bool is_loading) OVERRIDE {}
@@ skipping 252 matching lines @@
   TestRenderViewHost* active_test_rvh();
   TestWebContents* contents();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostImplTestHarness);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_TEST_RENDER_VIEW_HOST_H_