Handle JS mojo module fetch failures gracefully.

content/renderer/mojo_context_state.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_RENDERER_MOJO_CONTEXT_STATE_H_
 #define CONTENT_RENDERER_MOJO_CONTEXT_STATE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 37 matching lines @@
 
   // Invokes FetchModule() for any modules that have not already been
   // downloaded.
   void FetchModules(const std::vector<std::string>& ids);
 
   // Creates a ResourceFetcher to download |module|.
   void FetchModule(const std::string& module);
 
   // Callback once a module has finished downloading. Passes data to |runner_|.
   void OnFetchModuleComplete(ResourceFetcher* fetcher,
+                             const std::string& id,
                              const blink::WebURLResponse& response,
                              const std::string& data);
 
   // gin::ModuleRegistryObserver overrides:
   void OnDidAddPendingModule(
       const std::string& id,
       const std::vector<std::string>& dependencies) override;
 
   // Frame script is executed in. Also used to download resources.
   blink::WebFrame* frame_;
@@ skipping 12 matching lines @@
 
   // The prefix to use for all module requests.
   const std::string module_prefix_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoContextState);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MOJO_CONTEXT_STATE_H_