Fixed drag and drop into and out of Browser Plugin.

content/browser/browser_plugin/browser_plugin_embedder.h

 // Copyright (c) 2012 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.
 
 // A BrowserPluginEmbedder has a list of guests it manages.
 // In the beginning when a renderer sees one or more guests (BrowserPlugin
 // instance(s)) and there is a request to navigate to them, the WebContents for
 // that renderer creates a BrowserPluginEmbedder for itself. The
 // BrowserPluginEmbedder, in turn, manages a set of BrowserPluginGuests -- one
 // BrowserPluginGuest for each guest in the embedding WebContents. Note that
@@ skipping 113 matching lines @@
                      const BrowserPluginHostMsg_CreateGuest_Params& params);
   void OnPluginAtPositionResponse(int instance_id,
                                   int request_id,
                                   const gfx::Point& position);
   void OnPluginDestroyed(int instance_id);
   void OnSwapBuffersACK(int route_id,
                         int gpu_host_id,
                         const std::string& mailbox_name,
                         uint32 sync_point);
 
+  // Returns the guest browser plugin delegate that is currently dragging.
+  BrowserPluginGuest* GetDraggingGuest() const;
+
+  // Returns true if there is a guest currently being dragged over.
+  bool IsDragOverGuest() const;
+
   // Static factory instance (always NULL for non-test).
   static BrowserPluginHostFactory* factory_;
 
   // A scoped container for notification registries.
   NotificationRegistrar registrar_;
 
   // Contains guests' WebContents, mapping from their instance ids.
   ContainerInstanceMap guest_web_contents_by_instance_id_;
   RenderViewHost* render_view_host_;
   // Tracks the visibility state of the embedder.
   bool visible_;
   // Map that contains outstanding queries to |GetBrowserPluginAt|.
   // We need a roundtrip to renderer process to know the answer, therefore
   // storing these callbacks is required.
   typedef std::map<int, WebContents::GetRenderViewHostCallback>
       GetRenderViewHostCallbackMap;
   GetRenderViewHostCallbackMap pending_get_render_view_callbacks_;
   // Next request id for BrowserPluginMsg_PluginAtPositionRequest query.
   int next_get_render_view_request_id_;
   int next_instance_id_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPluginEmbedder);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BROWSER_PLUGIN_BROWSER_PLUGIN_EMBEDDER_H_