Make ChildProcessHost::DoLaunch() not touch a random set of things on a different thread.

shell/child_process_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 SHELL_CHILD_PROCESS_HOST_H_
 #define SHELL_CHILD_PROCESS_HOST_H_
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/process/process.h"
 #include "mojo/edk/embedder/channel_info_forward.h"
-#include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/public/cpp/bindings/error_handler.h"
 #include "shell/child_controller.mojom.h"
 
 namespace shell {
 
 class Context;
 
 // Child process host: parent-process representation of a child process, which
 // hosts/runs a native Mojo application loaded from the file system. This class
@@ skipping 27 matching lines @@
   // Like |ChildController::StartApp()|, but with one difference:
   // |on_app_complete| will *always* get called, even on connection error (or
   // even if the child process failed to start at all).
   void StartApp(const mojo::String& app_path,
                 mojo::InterfaceRequest<mojo::Application> application_request,
                 const ChildController::StartAppCallback& on_app_complete);
   void ExitNow(int32_t exit_code);
 
   // TODO(vtl): This is virtual, so tests can override it, but really |Start()|
   // should take a callback (see above) and this should be private.
-  virtual void DidStart(bool success);
+  virtual void DidStart(base::Process child_process);
 
  private:
+  struct LaunchData;
+
   // Callback for |mojo::embedder::CreateChannel()|.
   void DidCreateChannel(mojo::embedder::ChannelInfo* channel_info);
 
-  bool DoLaunch(const std::string& child_connection_id);
+  // Note: This is probably executed on a different thread (namely, using the
+  // blocking pool).
+  base::Process DoLaunch(scoped_ptr<LaunchData> launch_data);
 
   void AppCompleted(int32_t result);
 
   // |mojo::ErrorHandler| methods:
   void OnConnectionError() override;
 
   Context* const context_;
-  mojo::embedder::PlatformChannelPair platform_channel_pair_;
 
   ChildControllerPtr controller_;
   mojo::embedder::ChannelInfo* channel_info_;
   ChildController::StartAppCallback on_app_complete_;
 
   base::Process child_process_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildProcessHost);
 };
 
 }  // namespace shell
 
 #endif  // SHELL_CHILD_PROCESS_HOST_H_