Use ChannelMojo from the browser to NaCl loader process.

ppapi/nacl_irt/plugin_startup.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 "ppapi/nacl_irt/plugin_startup.h"
 
 #include "base/bind.h"
 #include "base/file_descriptor_posix.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 41 matching lines @@
     int browser_ipc_fd, int renderer_ipc_fd, int manifest_service_fd) {
   // The initialization must be only once.
   DCHECK_EQ(g_nacl_browser_ipc_fd, -1);
   DCHECK_EQ(g_nacl_renderer_ipc_fd, -1);
   DCHECK_EQ(g_manifest_service_fd, -1);
   g_nacl_browser_ipc_fd = browser_ipc_fd;
   g_nacl_renderer_ipc_fd = renderer_ipc_fd;
   g_manifest_service_fd = manifest_service_fd;
 }
 
-void StartUpPlugin() {
+void StartUpPlugin(bool initialize_mojo) {
   // The start up must be called only once.
   DCHECK(!g_shutdown_event);
   DCHECK(!g_io_thread);
 
-  // The Mojo EDK must be initialized before using IPC.
-  mojo::edk::Init();
+  // In some cases, Mojo has already been initialized, so we need to avoid
+  // double-initializing it.
+  if (initialize_mojo) {
+    // The Mojo EDK must be initialized before using IPC.
+    mojo::edk::Init();
+  }
 
   g_shutdown_event =
       new base::WaitableEvent(base::WaitableEvent::ResetPolicy::MANUAL,
                               base::WaitableEvent::InitialState::NOT_SIGNALED);
   g_io_thread = new base::Thread("Chrome_NaClIOThread");
   g_io_thread->StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
 
   if (g_manifest_service_fd != -1) {
     // Manifest service must be created on IOThread so that the main message
@@ skipping 34 matching lines @@
   // The IOThread must be initialized in advance.
   DCHECK(g_io_thread);
   return g_io_thread;
 }
 
 ManifestService* GetManifestService() {
   return g_manifest_service;
 }
 
 }  // namespace ppapi