Dragging shouldn't block interstitial page.

content/browser/frame_host/interstitial_page_impl.cc

 // Copyright 2013 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/frame_host/interstitial_page_impl.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 855 matching lines @@
   NOTREACHED() << "InterstitialPage does not support showing popup menus.";
 }
 #endif
 
 void InterstitialPageImpl::InterstitialPageRVHDelegateView::StartDragging(
     const DropData& drop_data,
     WebDragOperationsMask allowed_operations,
     const gfx::ImageSkia& image,
     const gfx::Vector2d& image_offset,
     const DragEventSourceInfo& event_info) {
-  NOTREACHED() << "InterstitialPage does not support dragging yet.";
+  interstitial_page_->render_view_host_->DragSourceSystemDragEnded();
+  DVLOG(1) << "InterstitialPage does not support dragging yet.";
 }
 
 void InterstitialPageImpl::InterstitialPageRVHDelegateView::UpdateDragCursor(
     WebDragOperation) {
   NOTREACHED() << "InterstitialPage does not support dragging yet.";
 }
 
 void InterstitialPageImpl::InterstitialPageRVHDelegateView::GotFocus() {
   WebContents* web_contents = interstitial_page_->web_contents();
   if (web_contents && web_contents->GetDelegate())
@@ skipping 11 matching lines @@
 
   web_contents->GetDelegateView()->TakeFocus(reverse);
 }
 
 void InterstitialPageImpl::InterstitialPageRVHDelegateView::OnFindReply(
     int request_id, int number_of_matches, const gfx::Rect& selection_rect,
     int active_match_ordinal, bool final_update) {
 }
 
 }  // namespace content