Update MimeSniffingResourceHandler tests to use MockResourceLoader.

content/browser/loader/mime_sniffing_resource_handler.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/loader/mime_sniffing_resource_handler.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 227 matching lines @@
   }
 
   // If the BufferingHandler is acting as a pass-through handler, just ask the
   // upwards ResourceController to resume the request.
   if (state_ == STATE_STARTING || state_ == STATE_STREAMING) {
     controller()->Resume();
     return;
   }
 
   // Otherwise proceed with the replay of the response. If it is successful,
-  // it will resume the request.
-  AdvanceState();
+  // it will resume the request. Posted as a task to avoid re-entrancy into
+  // the calling class.
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&MimeSniffingResourceHandler::AdvanceState,
+                            weak_ptr_factory_.GetWeakPtr()));
 }
 
 void MimeSniffingResourceHandler::Cancel() {
   controller()->Cancel();
 }
 
 void MimeSniffingResourceHandler::CancelAndIgnore() {
   controller()->CancelAndIgnore();
 }
 
@@ skipping 247 matching lines @@
 
 void MimeSniffingResourceHandler::OnPluginsLoaded(
     const std::vector<WebPluginInfo>& plugins) {
   // No longer blocking on the plugins being loaded.
   request()->LogUnblocked();
   if (state_ == STATE_BUFFERING)
     AdvanceState();
 }
 
 }  // namespace content