Adds plumbing to pass WebUI mojo::Handle from browser to renderer

content/common/mojo/mojo_channel_init.h

Index: content/common/mojo/mojo_channel_init.h
diff --git a/content/common/mojo/mojo_channel_init.h b/content/common/mojo/mojo_channel_init.h
index 44ba07d50ad3d4944f1c06267db944fe5e00425e..44fa8f47da269cb2fdcfb02c9844d7e2bbb65470 100644
--- a/content/common/mojo/mojo_channel_init.h
+++ b/content/common/mojo/mojo_channel_init.h
@@ -31,12 +31,20 @@ class CONTENT_EXPORT MojoChannelInit {
   MojoChannelInit();
   ~MojoChannelInit();
 
+  // Initializes mojo. This is done implicitly when creating a MojoChannelInit,
+  // but can be done explicitly as necessary.
+  static void InitMojo();
+
   // Inits the channel. This takes ownership of |file|.
   void Init(base::PlatformFile file,
             scoped_refptr<base::TaskRunner> io_thread_task_runner);
 
   bool is_handle_valid() const { return bootstrap_message_pipe_.is_valid(); }
 
+  mojo::ScopedMessagePipeHandle bootstrap_message_pipe() {
+    return bootstrap_message_pipe_.Pass();
+  }
+
  private:
   // Invoked on the main thread once the channel has been established.
   static void OnCreatedChannel(