Extract minimal RenderViewHost interface for embedders, leaving

content/browser/tab_contents/web_drag_dest_gtk.h

Index: content/browser/tab_contents/web_drag_dest_gtk.h
diff --git a/content/browser/tab_contents/web_drag_dest_gtk.h b/content/browser/tab_contents/web_drag_dest_gtk.h
index 8fac750bbb71e540e57d2b9657eca192a2b5839f..c394da6e8e538e6f2aa12b06d1ac55e1482f983e 100644
--- a/content/browser/tab_contents/web_drag_dest_gtk.h
+++ b/content/browser/tab_contents/web_drag_dest_gtk.h
@@ -16,6 +16,8 @@
 #include "ui/base/gtk/gtk_signal.h"
 #include "webkit/glue/webdropdata.h"
 
+class RenderViewHostImpl;
+
 namespace content {
 
 class WebContents;
@@ -40,6 +42,8 @@ class CONTENT_EXPORT WebDragDestGtk {
   void set_delegate(WebDragDestDelegate* delegate) { delegate_ = delegate; }
 
  private:
+  RenderViewHostImpl* GetRenderViewHost() const;
+
   // Called when a system drag crosses over the render view. As there is no drag
   // enter event, we treat it as an enter event (and not a regular motion event)
   // when |context_| is NULL.