Drag-and-drop: Target drag messages to specific RenderWidgets.

content/browser/web_contents/web_contents_view_child_frame.cc

 // Copyright (c) 2016 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.
 
 #include "content/browser/web_contents/web_contents_view_child_frame.h"
 
 #include "build/build_config.h"
 #include "content/browser/frame_host/render_widget_host_view_child_frame.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents_view_delegate.h"
@@ skipping 149 matching lines @@
     RenderFrameHost* render_frame_host,
     const ContextMenuParams& params) {
   NOTREACHED();
 }
 
 void WebContentsViewChildFrame::StartDragging(
     const DropData& drop_data,
     WebDragOperationsMask ops,
     const gfx::ImageSkia& image,
     const gfx::Vector2d& image_offset,
-    const DragEventSourceInfo& event_info) {
+    const DragEventSourceInfo& event_info,
+    RenderWidgetHostImpl* source_rwh) {
   NOTREACHED();
 }
 
 }  // namespace content