Make mojo_system static and mojo_system_impl a component, never use both

mojo/shell/app_child_process.cc

 // 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.
 
 #include "mojo/shell/app_child_process.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 73 matching lines @@
 
 // Should be created and initialized on the main thread.
 class AppContext {
  public:
   AppContext()
       : io_thread_("io_thread"),
         controller_thread_("controller_thread") {}
   ~AppContext() {}
 
   void Init() {
-    // Initialize Mojo before starting any threads.
-    embedder::Init();
-
     // Create and start our I/O thread.
     base::Thread::Options io_thread_options(base::MessageLoop::TYPE_IO, 0);
     CHECK(io_thread_.StartWithOptions(io_thread_options));
     io_runner_ = io_thread_.message_loop_proxy().get();
     CHECK(io_runner_);
 
     // Create and start our controller thread.
     base::Thread::Options controller_thread_options;
     controller_thread_options.message_loop_type =
         base::MessageLoop::TYPE_CUSTOM;
@@ skipping 186 matching lines @@
   blocker.Block();
 
   app_context.controller_runner()->PostTask(
       FROM_HERE,
       base::Bind(&AppChildControllerImpl::Shutdown,
       base::Unretained(app_context.controller())));
 }
 
 }  // namespace shell
 }  // namespace mojo