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

content/browser/renderer_host/render_widget_host_view_mac.h

Index: content/browser/renderer_host/render_widget_host_view_mac.h
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.h b/content/browser/renderer_host/render_widget_host_view_mac.h
index c1ab8636dbca08e484ceb934d1e0e0e2b16a076e..89eaf484c611effa3a767839c6ceb4a5b140ef47 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -229,7 +229,8 @@ class RenderWidgetHostViewMac : public RenderWidgetHostViewBase {
 
   // Implementation of RenderWidgetHostViewPort.
   virtual void InitAsPopup(RenderWidgetHostView* parent_host_view,
-                           const gfx::Rect& pos) OVERRIDE;
+                           const gfx::Rect& pos,
+                           WebContentsViewDelegate* delegate) OVERRIDE;
   virtual void InitAsFullscreen(
       RenderWidgetHostView* reference_host_view) OVERRIDE;
   virtual void WasShown() OVERRIDE;
@@ -476,6 +477,9 @@ class RenderWidgetHostViewMac : public RenderWidgetHostViewBase {
   // selected text on the renderer.
   std::string selected_text_;
 
+  // The window used for popup widgets.
+  scoped_nsobject<NSWindow> popup_window_;
+
   // The fullscreen window used for pepper flash.
   scoped_nsobject<NSWindow> pepper_fullscreen_window_;
   scoped_nsobject<FullscreenWindowManager> fullscreen_window_manager_;