Require a default parent to use some Views implementations on ChromeOS.

chrome/browser/ui/views/tab_contents/native_tab_contents_view_gtk.cc

 // Copyright (c) 2011 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 "chrome/browser/ui/views/tab_contents/native_tab_contents_view_gtk.h"
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/renderer_host/render_widget_host_view_gtk.h"
 #include "chrome/browser/tab_contents/web_drag_dest_gtk.h"
 #include "chrome/browser/ui/gtk/constrained_window_gtk.h"
 #include "chrome/browser/ui/gtk/tab_contents_drag_source.h"
 #include "chrome/browser/ui/views/tab_contents/native_tab_contents_view_delegate.h"
 #include "chrome/browser/ui/views/tab_contents/native_tab_contents_view_views.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/browser/tab_contents/tab_contents_view.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDragData.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
+#include "views/views_delegate.h"
 
 using WebKit::WebDragOperation;
 using WebKit::WebDragOperationsMask;
 using WebKit::WebInputEvent;
 
 namespace {
 
 // Called when the content view gtk widget is tabbed to, or after the call to
 // gtk_widget_child_focus() in TakeFocus(). We return true
 // and grab focus if we don't have it. The call to
@@ skipping 226 matching lines @@
     PositionChild(widget, child_x, 0, 0, 0);
   }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeTabContentsView, public:
 
 // static
 NativeTabContentsView* NativeTabContentsView::CreateNativeTabContentsView(
     internal::NativeTabContentsViewDelegate* delegate) {
-  if (views::Widget::IsPureViews())
+  if (views::Widget::IsPureViews() &&
+      views::ViewsDelegate::views_delegate->GetDefaultParentView())
     return new NativeTabContentsViewViews(delegate);
   return new NativeTabContentsViewGtk(delegate);
 }
-