Moves android specific code into android directory

shell/android/ui_application_loader_android.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 SHELL_UI_APPLICATION_LOADER_ANDROID_H_
-#define SHELL_UI_APPLICATION_LOADER_ANDROID_H_
+#ifndef SHELL_ANDROID_UI_APPLICATION_LOADER_ANDROID_H_
+#define SHELL_ANDROID_UI_APPLICATION_LOADER_ANDROID_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "mojo/application_manager/application_loader.h"
 
+namespace base {
+class MessageLoop;
+}
+
 namespace mojo {
 
 class ApplicationManager;
 
-namespace shell {
-class Context;
-}
-
 // ApplicationLoader implementation that creates a background thread and issues
 // load
 // requests there.
 class UIApplicationLoader : public ApplicationLoader {
  public:
   UIApplicationLoader(scoped_ptr<ApplicationLoader> real_loader,
-                      shell::Context* context);
+                      base::MessageLoop* ui_message_loop);
   ~UIApplicationLoader() override;
 
   // ApplicationLoader overrides:
   void Load(ApplicationManager* manager,
             const GURL& url,
             ScopedMessagePipeHandle shell_handle,
             LoadCallback callback) override;
   void OnApplicationError(ApplicationManager* manager,
                           const GURL& url) override;
 
  private:
   class UILoader;
 
   // These functions are exected on the background thread. They call through
   // to |background_loader_| to do the actual loading.
   // TODO: having this code take a |manager| is fragile (as ApplicationManager
   // isn't thread safe).
   void LoadOnUIThread(ApplicationManager* manager,
                       const GURL& url,
                       ScopedMessagePipeHandle shell_handle);
   void OnApplicationErrorOnUIThread(ApplicationManager* manager,
                                     const GURL& url);
   void ShutdownOnUIThread();
 
   scoped_ptr<ApplicationLoader> loader_;
-  shell::Context* context_;
+  base::MessageLoop* ui_message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(UIApplicationLoader);
 };
 
 }  // namespace mojo
 
-#endif  // SHELL_UI_APPLICATION_LOADER_ANDROID_H_
+#endif  // SHELL_ANDROID_UI_APPLICATION_LOADER_ANDROID_H_