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

content/port/browser/render_widget_host_view_port.h

Index: content/port/browser/render_widget_host_view_port.h
diff --git a/content/port/browser/render_widget_host_view_port.h b/content/port/browser/render_widget_host_view_port.h
index 6d4806a3572f7f06ee937943ed0bc19f1dfeee5a..ff42a77195e62ca1006d999747f484dd1492eb40 100644
--- a/content/port/browser/render_widget_host_view_port.h
+++ b/content/port/browser/render_widget_host_view_port.h
@@ -43,6 +43,7 @@ class PlatformBitmap;
 namespace content {
 class BackingStore;
 class SmoothScrollGesture;
+class WebContentsViewDelegate;
 struct NativeWebKeyboardEvent;
 
 // This is the larger RenderWidgetHostView interface exposed only
@@ -62,7 +63,8 @@ class CONTENT_EXPORT RenderWidgetHostViewPort : public RenderWidgetHostView {
   // Perform all the initialization steps necessary for this object to represent
   // a popup (such as a <select> dropdown), then shows the popup at |pos|.
   virtual void InitAsPopup(RenderWidgetHostView* parent_host_view,
-                           const gfx::Rect& pos) = 0;
+                           const gfx::Rect& pos,
+                           WebContentsViewDelegate* delegate = NULL) = 0;
 
   // Perform all the initialization steps necessary for this object to represent
   // a full screen window.