Fix the crash that could occur when the window is closed while web contents drag is in progress.

content/browser/web_contents/web_contents_impl.cc

 // 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.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 2796 matching lines @@
 void WebContentsImpl::UpdateTargetURL(int32 page_id, const GURL& url) {
   if (delegate_)
     delegate_->UpdateTargetURL(this, page_id, url);
 }
 
 void WebContentsImpl::Close(RenderViewHost* rvh) {
   // The UI may be in an event-tracking loop, such as between the
   // mouse-down and mouse-up in text selection or a button click.
   // Defer the close until after tracking is complete, so that we
   // don't free objects out from under the UI.
-  // TODO(shess): This could probably be integrated with the
-  // IsDoingDrag() test below.  Punting for now because I need more
-  // research to understand how this impacts platforms other than Mac.
   // TODO(shess): This could get more fine-grained.  For instance,
   // closing a tab in another window while selecting text in the
   // current window's Omnibox should be just fine.
   if (GetView()->IsEventTracking()) {
     GetView()->CloseTabAfterEventTracking();
     return;
   }
 
-  // If we close the tab while we're in the middle of a drag, we'll crash.
-  // Instead, cancel the drag and close it as soon as the drag ends.
-  if (GetView()->IsDoingDrag()) {
-    GetView()->CancelDragAndCloseTab();
-    return;
-  }
-
   // Ignore this if it comes from a RenderViewHost that we aren't showing.
   if (delegate_ && rvh == GetRenderViewHost())
     delegate_->CloseContents(this);
 }
 
 void WebContentsImpl::SwappedOut(RenderViewHost* rvh) {
   if (delegate_ && rvh == GetRenderViewHost())
     delegate_->SwappedOut(this);
 }
 
@@ skipping 546 matching lines @@
   }
 }
 
 content::BrowserPluginGuest* WebContentsImpl::GetBrowserPluginGuest() {
   return browser_plugin_guest_.get();
 }
 
 content::BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() {
   return browser_plugin_embedder_.get();
 }