Fixed drag and drop into and out of Browser Plugin.

content/browser/web_contents/web_drag_source_mac.mm

 // 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 "content/browser/web_contents/web_drag_source_mac.h"
 
 #include <sys/param.h>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
@@ skipping 264 matching lines @@
     // Flip |screenPoint|.
     NSRect screenFrame = [[[contentsView_ window] screen] frame];
     screenPoint.y = screenFrame.size.height - screenPoint.y;
 
     // If AppKit returns a copy and move operation, mask off the move bit
     // because WebCore does not understand what it means to do both, which
     // results in an assertion failure/renderer crash.
     if (operation == (NSDragOperationMove | NSDragOperationCopy))
       operation &= ~NSDragOperationMove;
 
-    rvh->DragSourceEndedAt(localPoint.x, localPoint.y,
-                           screenPoint.x, screenPoint.y,
-                           static_cast<WebKit::WebDragOperation>(operation));
+    contents_->DragSourceEndedAt(localPoint.x, localPoint.y, screenPoint.x,
+        screenPoint.y, static_cast<WebKit::WebDragOperation>(operation));
   }
 
   // Make sure the pasteboard owner isn't us.
   [pasteboard_ declareTypes:[NSArray array] owner:nil];
 }
 
 - (void)moveDragTo:(NSPoint)screenPoint {
   if (!contents_)
     return;
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       contents_->GetRenderViewHost());
   if (rvh) {
     // Convert |screenPoint| to view coordinates and flip it.
     NSPoint localPoint = NSMakePoint(0, 0);
     if ([contentsView_ window])
       localPoint = [self convertScreenPoint:screenPoint];
     NSRect viewFrame = [contentsView_ frame];
     localPoint.y = viewFrame.size.height - localPoint.y;
     // Flip |screenPoint|.
     NSRect screenFrame = [[[contentsView_ window] screen] frame];
     screenPoint.y = screenFrame.size.height - screenPoint.y;
 
-    rvh->DragSourceMovedTo(localPoint.x, localPoint.y,
-                           screenPoint.x, screenPoint.y);
+    contents_->DragSourceMovedTo(localPoint.x, localPoint.y,
+                                 screenPoint.x, screenPoint.y);
   }
 }
 
 - (NSString*)dragPromisedFileTo:(NSString*)path {
   // Be extra paranoid; avoid crashing.
   if (!dropData_.get()) {
     NOTREACHED() << "No drag-and-drop data available for promised file.";
     return nil;
   }
 
@@ skipping 140 matching lines @@
 - (NSImage*)dragImage {
   if (dragImage_)
     return dragImage_;
 
   // Default to returning a generic image.
   return content::GetContentClient()->GetNativeImageNamed(
       IDR_DEFAULT_FAVICON).ToNSImage();
 }
 
 @end  // @implementation WebDragSource (Private)