Gracefully handle mixed content checking on detached resource fetches.

Source/core/loader/PingLoader.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include "core/dom/Document.h"
 #include "core/fetch/FetchContext.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/fetch/UniqueIdentifier.h"
 #include "core/frame/FrameConsole.h"
 #include "core/frame/LocalFrame.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
+#include "core/loader/MixedContentChecker.h"
 #include "core/page/Page.h"
 #include "platform/exported/WrappedResourceRequest.h"
 #include "platform/network/ResourceError.h"
 #include "platform/network/ResourceRequest.h"
 #include "platform/network/ResourceResponse.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "platform/weborigin/SecurityPolicy.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebURLLoader.h"
 #include "public/platform/WebURLRequest.h"
@@ skipping 165 matching lines @@
     InspectorInstrumentation::didFailLoading(frame, m_identifier, ResourceError::cancelledError(m_url));
     frame->console().didFailLoading(m_identifier, ResourceError::cancelledError(m_url));
 }
 
 DEFINE_TRACE(PingLoader)
 {
     PageLifecycleObserver::trace(visitor);
 }
 
 }