Moves android specific code into android directory

shell/context.h

 // Copyright 2013 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_CONTEXT_H_
 #define SHELL_CONTEXT_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "mojo/application_manager/application_manager.h"
 #include "shell/mojo_url_resolver.h"
 #include "shell/task_runners.h"
 
-#if defined(OS_ANDROID)
-#include "base/android/scoped_java_ref.h"
-#endif  // defined(OS_ANDROID)
-
 namespace mojo {
 
 class Spy;
 
 namespace shell {
 
 class DynamicApplicationLoader;
 class ExternalApplicationListener;
 
 // The "global" context for the shell's main process.
 class Context : ApplicationManager::Delegate {
  public:
   Context();
   ~Context() override;
 
   static void EnsureEmbedderIsInitialized();
   bool Init();
 
   void Run(const GURL& url);
   ScopedMessagePipeHandle ConnectToServiceByName(
       const GURL& application_url,
       const std::string& service_name);
 
   TaskRunners* task_runners() { return task_runners_.get(); }
   ApplicationManager* application_manager() { return &application_manager_; }
   MojoURLResolver* mojo_url_resolver() { return &mojo_url_resolver_; }
 
-#if defined(OS_ANDROID)
-  base::MessageLoop* ui_loop() const { return ui_loop_; }
-  void set_ui_loop(base::MessageLoop* ui_loop) { ui_loop_ = ui_loop; }
-#endif  // defined(OS_ANDROID)
-
  private:
   class NativeViewportApplicationLoader;
 
   // ApplicationManager::Delegate override.
   void OnApplicationError(const GURL& url) override;
   GURL ResolveURL(const GURL& url) override;
 
   std::set<GURL> app_urls_;
   scoped_ptr<TaskRunners> task_runners_;
   scoped_ptr<ExternalApplicationListener> listener_;
   ApplicationManager application_manager_;
   MojoURLResolver mojo_url_resolver_;
   scoped_ptr<Spy> spy_;
-#if defined(OS_ANDROID)
-  base::MessageLoop* ui_loop_;
-#endif  // defined(OS_ANDROID)
 
   DISALLOW_COPY_AND_ASSIGN(Context);
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // SHELL_CONTEXT_H_