Revert of Use a token to initialise ChannelMojo and MojoApplication everywhere.

content/browser/mojo/mojo_application_host.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_BROWSER_MOJO_MOJO_APPLICATION_HOST_H_
 #define CONTENT_BROWSER_MOJO_MOJO_APPLICATION_HOST_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
+#include "base/process/process_handle.h"
 #include "build/build_config.h"
 #include "content/common/application_setup.mojom.h"
+#include "content/common/mojo/channel_init.h"
 #include "content/common/mojo/service_registry_impl.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+#include "mojo/public/cpp/system/message_pipe.h"
 
 #if defined(OS_ANDROID)
 #include "content/public/browser/android/service_registry_android.h"
 #endif
 
 namespace IPC {
 class Sender;
 }
 
 namespace content {
 
 // MojoApplicationHost represents the code needed on the browser side to setup
-// a child process as a Mojo application. The child process should use the token
-// from GetToken() to initialize its MojoApplication. MojoApplicationHost makes
-// the ServiceRegistry interface available so that child-provided services can
-// be invoked.
+// a child process as a Mojo application via Chrome IPC. The child process
+// should use MojoApplication to handle messages generated by an instance of
+// MojoApplicationHost. MojoApplicationHost makes the ServiceRegistry interface
+// available so that child-provided services can be invoked.
 class CONTENT_EXPORT MojoApplicationHost {
  public:
   MojoApplicationHost();
   ~MojoApplicationHost();
 
-  // Returns a token to pass to the child process to initialize its
-  // MojoApplication.
-  const std::string& GetToken() { return token_; }
+  // Two-phase initialization:
+  //  1- Init makes service_registry() available synchronously.
+  //  2- Activate establishes the actual connection to the peer process.
+  bool Init();
+  void Activate(IPC::Sender* sender, base::ProcessHandle process_handle);
+
+  // Use a shared token to initialize the application. Returns a token to pass
+  // to the child process.
+  std::string InitWithToken();
 
   ServiceRegistry* service_registry() { return &service_registry_; }
 
 #if defined(OS_ANDROID)
   ServiceRegistryAndroid* service_registry_android() {
     return service_registry_android_.get();
   }
 #endif
 
+  void OverrideIOTaskRunnerForTest(
+      scoped_refptr<base::TaskRunner> io_task_runner);
+
  private:
-  const std::string token_;
+  ChannelInit channel_init_;
+  mojo::edk::ScopedPlatformHandle client_handle_;
+
+  bool did_activate_;
 
   std::unique_ptr<mojom::ApplicationSetup> application_setup_;
   ServiceRegistryImpl service_registry_;
 
+  scoped_refptr<base::TaskRunner> io_task_runner_override_;
+
 #if defined(OS_ANDROID)
   std::unique_ptr<ServiceRegistryAndroid> service_registry_android_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(MojoApplicationHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MOJO_MOJO_APPLICATION_HOST_H_