Avoid a thread hop when initializing IPC to new processes

content/browser/child_process_launcher_helper.h

Index: content/browser/child_process_launcher_helper.h
diff --git a/content/browser/child_process_launcher_helper.h b/content/browser/child_process_launcher_helper.h
index ead7d44f4936bc5dee5fcdc0d86a7f0b2522fe4d..51dad0ac45569365096fc9f8d45e8a444492cf0a 100644
--- a/content/browser/child_process_launcher_helper.h
+++ b/content/browser/child_process_launcher_helper.h
@@ -15,6 +15,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/result_codes.h"
 #include "mojo/edk/embedder/embedder.h"
+#include "mojo/edk/embedder/pending_process_connection.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 
 #if defined(OS_WIN)
@@ -73,6 +74,8 @@ class ChildProcessLauncherHelper :
       BrowserThread::ID client_thread_id,
       std::unique_ptr<base::CommandLine> command_line,
       std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
+      std::unique_ptr<mojo::edk::PendingProcessConnection> pending_connection,
+      const mojo::edk::ProcessErrorCallback& process_error_callback,
       const base::WeakPtr<ChildProcessLauncher>& child_process_launcher,
       bool terminate_on_shutdown);
 
@@ -101,13 +104,18 @@ class ChildProcessLauncherHelper :
   // |is_synchronous_launch| is set to false if the starting of the process is
   // asynchonous (this is the case on Android), in which case the returned
   // Process is not valid (and PostLaunchOnLauncherThread() will provide the
-  // process once it is available).
+  // process once it is available). Iff |is_synchronous_launch| is set to false,
+  // the implementation must also take ownership of |*pending_connection| and
+  // |*server_handle| to eventually pass them on to
+  // PostLaunchOnLauncherThread().
   // Platform specific.
   ChildProcessLauncherHelper::Process LaunchProcessOnLauncherThread(
       const base::LaunchOptions& options,
       std::unique_ptr<FileMappedForLaunch> files_to_register,
       bool* is_synchronous_launch,
-      int* launch_result);
+      int* launch_result,
+      std::unique_ptr<mojo::edk::PendingProcessConnection>* pending_connection,
+      mojo::edk::ScopedPlatformHandle* server_handle);
 
   // Called right after the process has been launched, whether it was created
   // yet or not.
@@ -119,9 +127,12 @@ class ChildProcessLauncherHelper :
   // Called once the process has been created, successfully or not.
   // If |post_launch_on_client_thread_called| is false,
   // this calls PostLaunchOnClientThread on the client thread.
-  void PostLaunchOnLauncherThread(ChildProcessLauncherHelper::Process process,
-                                  int launch_result,
-                                  bool post_launch_on_client_thread_called);
+  void PostLaunchOnLauncherThread(
+      ChildProcessLauncherHelper::Process process,
+      int launch_result,
+      bool post_launch_on_client_thread_called,
+      std::unique_ptr<mojo::edk::PendingProcessConnection> pending_connection,
+      mojo::edk::ScopedPlatformHandle server_handle);
 
   // Note that this could be called before PostLaunchOnLauncherThread() is
   // called.
@@ -160,7 +171,9 @@ class ChildProcessLauncherHelper :
 
   ~ChildProcessLauncherHelper();
 
-  void LaunchOnLauncherThread();
+  void LaunchOnLauncherThread(
+      std::unique_ptr<mojo::edk::PendingProcessConnection> pending_connection,
+      mojo::edk::ScopedPlatformHandle server_handle);
 
   const mojo::edk::PlatformHandle& mojo_client_handle() const {
     return mojo_client_handle_.get();
@@ -178,9 +191,10 @@ class ChildProcessLauncherHelper :
   base::TimeTicks begin_launch_time_;
   std::unique_ptr<base::CommandLine> command_line_;
   std::unique_ptr<SandboxedProcessLauncherDelegate> delegate_;
+  std::unique_ptr<mojo::edk::PendingProcessConnection> pending_connection_;
+  const mojo::edk::ProcessErrorCallback process_error_callback_;
   base::WeakPtr<ChildProcessLauncher> child_process_launcher_;
   mojo::edk::ScopedPlatformHandle mojo_client_handle_;
-  mojo::edk::ScopedPlatformHandle mojo_server_handle_;
   bool terminate_on_shutdown_;
 };