Teach sky_viewer about the new main.dart hotness

sky/engine/core/script/dart_controller.h

 // Copyright 2015 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 SKY_ENGINE_CORE_SCRIPT_DART_CONTROLLER_H_
 #define SKY_ENGINE_CORE_SCRIPT_DART_CONTROLLER_H_
 
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "dart/runtime/include/dart_api.h"
+#include "mojo/services/network/public/interfaces/url_loader.mojom.h"
 #include "sky/engine/wtf/OwnPtr.h"
 #include "sky/engine/wtf/text/AtomicString.h"
 #include "sky/engine/wtf/text/TextPosition.h"
 
 namespace blink {
 class AbstractModule;
 class BuiltinSky;
 class DOMDartState;
 class DartValue;
 class HTMLScriptElement;
 class KURL;
 class View;
 
 class DartController {
  public:
   DartController();
   ~DartController();
 
   static void InitVM();
 
   typedef base::Callback<void(RefPtr<AbstractModule>, RefPtr<DartValue>)>
       LoadFinishedCallback;
 
-  void LoadMainLibrary(const KURL& url);
+  // Can either issue the url load ourselves or take an existing response:
+  void LoadMainLibrary(const KURL& url, mojo::URLResponsePtr response = nullptr);
 
   void LoadScriptInModule(AbstractModule* module,
                           const String& source,
                           const TextPosition& textPosition,
                           const LoadFinishedCallback& load_finished_callback);
   void ExecuteLibraryInModule(AbstractModule* module,
                               Dart_Handle library,
                               HTMLScriptElement* script);
 
   void ClearForClose();
@@ skipping 15 matching lines @@
   OwnPtr<BuiltinSky> builtin_sky_;
 
   base::WeakPtrFactory<DartController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DartController);
 };
 
 }
 
 #endif // SKY_ENGINE_CORE_SCRIPT_DART_CONTROLLER_H_