Added warning when URLRequestContextGetter leaks.

net/url_request/url_request_context_getter.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 "net/url_request/url_request_context_getter.h"
 
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "net/url_request/url_request_context.h"
 
 namespace net {
 
 URLRequestContextGetter::URLRequestContextGetter() {}
 
 URLRequestContextGetter::~URLRequestContextGetter() {}
 
 void URLRequestContextGetter::OnDestruct() const {
   scoped_refptr<base::SingleThreadTaskRunner> network_task_runner =
       GetNetworkTaskRunner();
   DCHECK(network_task_runner);
   if (network_task_runner) {
     if (network_task_runner->BelongsToCurrentThread()) {
       delete this;
     } else {
-      network_task_runner->DeleteSoon(FROM_HERE, this);
+      if (!network_task_runner->DeleteSoon(FROM_HERE, this)) {
+        // Can't force-delete the object here, because some derived classes
+        // can only be deleted on the owning thread, so just emit a warning to
+        // aid in debugging.
+        DLOG(WARNING) << "URLRequestContextGetter leaking due to no owning"
+                      << " thread.";
+      }
     }
   }
   // If no IO message loop proxy was available, we will just leak memory.
   // This is also true if the IO thread is gone.
 }
 
 }  // namespace net