Drag-and-drop: Target drag messages (the sequel).

content/browser/web_contents/web_drag_dest_mac.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.
 
 #import <Cocoa/Cocoa.h>
 
 #include <memory>
 
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
 #include "content/public/common/drop_data.h"
 
 namespace content {
+class RenderWidgetHostImpl;
 class RenderViewHost;
 class WebContentsImpl;
 class WebDragDestDelegate;
 }
 
 // A typedef for a RenderViewHost used for comparison purposes only.
 typedef content::RenderViewHost* RenderViewHostIdentifier;
 
 // A class that handles tracking and event processing for a drag and drop
 // over the content area. Assumes something else initiates the drag, this is
 // only for processing during a drag.
 CONTENT_EXPORT
 @interface WebDragDest : NSObject {
  @private
   // Our associated WebContentsImpl. Weak reference.
   content::WebContentsImpl* webContents_;
 
   // Delegate; weak.
   content::WebDragDestDelegate* delegate_;
 
   // Updated asynchronously during a drag to tell us whether or not we should
   // allow the drop.
   NSDragOperation currentOperation_;
 
+  // Tracks the current RenderWidgetHost we're dragging over.
+  base::WeakPtr<content::RenderWidgetHostImpl> currentRWHForDrag_;
+
   // Keep track of the render view host we're dragging over.  If it changes
   // during a drag, we need to re-send the DragEnter message.
   RenderViewHostIdentifier currentRVH_;
 
   // The data for the current drag, or NULL if none is in progress.
   std::unique_ptr<content::DropData> dropData_;
 
   // True if the drag has been canceled.
   bool canceled_;
 }
@@ skipping 32 matching lines @@
              fromPasteboard:(NSPasteboard*)pboard;
 // Given a point in window coordinates and a view in that window, return a
 // flipped point in the coordinate system of |view|.
 - (NSPoint)flipWindowPointToView:(const NSPoint&)windowPoint
                             view:(NSView*)view;
 // Given a point in window coordinates and a view in that window, return a
 // flipped point in screen coordinates.
 - (NSPoint)flipWindowPointToScreen:(const NSPoint&)windowPoint
                               view:(NSView*)view;
 @end