Create a visible window with class name Chrome_RenderWidgetHostHWND which corresponds to the bounds…

content/browser/renderer_host/render_widget_host_view_aura.h

Index: content/browser/renderer_host/render_widget_host_view_aura.h
===================================================================
--- content/browser/renderer_host/render_widget_host_view_aura.h	(revision 249488)
+++ content/browser/renderer_host/render_widget_host_view_aura.h	(working copy)
@@ -67,6 +67,10 @@
 }
 
 namespace content {
+#if defined(OS_WIN)
+class LegacyRenderWidgetHostHWND;
+#endif
+
 class RenderWidgetHostImpl;
 class RenderWidgetHostView;
 class ResizeLock;
@@ -768,10 +772,12 @@
   base::WeakPtrFactory<RenderWidgetHostViewAura> weak_ptr_factory_;
 
 #if defined(OS_WIN)
-  // The dummy HWND which corresponds to the bounds of the web page. This is
-  // passed to windowless plugins like Flash/Silverlight, etc as the
-  // container window.
-  HWND plugin_parent_window_;
+  // The LegacyRenderWidgetHostHWND class provides a dummy HWND which is used
+  // for accessibility, as the container for windowless plugins like
+  // Flash/Silverlight, etc and for legacy drivers for trackpoints/trackpads,
+  // etc.
+  scoped_ptr<content::LegacyRenderWidgetHostHWND>
+      legacy_render_widget_host_HWND_;
 #endif
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAura);
 };