Adds the ability for the renderer to create the mojo channel

content/common/mojo/mojo_channel_init.cc

Index: content/common/mojo/mojo_channel_init.cc
diff --git a/content/common/mojo/mojo_channel_init.cc b/content/common/mojo/mojo_channel_init.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b146ecac9d0bb338d3111a307e1f7ebd4fac1d77
--- /dev/null
+++ b/content/common/mojo/mojo_channel_init.cc
@@ -0,0 +1,94 @@
+// Copyright (c) 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 "content/common/mojo/mojo_channel_init.h"
+
+#include "base/bind.h"
+#include "base/lazy_instance.h"
+#include "base/message_loop/message_loop.h"
+#include "base/synchronization/lock.h"
+#include "mojo/system/embedder/embedder.h"
+
+namespace content {
+
+namespace {
+
+// Initializes mojo. Use a lock to ensure we only do this once.
+// TODO(sky): this likely wants to move to a more central location, such as
+// startup.
+void InitMojo() {
+  static base::LazyInstance<base::Lock> lock = LAZY_INSTANCE_INITIALIZER;
+  static bool inited = false;
+  base::AutoLock auto_lock(lock.Get());
+  if (!inited) {
+    inited = true;
+    mojo::embedder::Init();
+  }
+}
+
+}  // namespace
+
+MojoChannelInit::MojoChannelInit()
+    : main_thread_(base::MessageLoop::current()->message_loop_proxy()),
+      channel_info_(NULL),
+      weak_factory_(this) {
+}
+
+MojoChannelInit::~MojoChannelInit() {
+  handle_.reset();
+  if (channel_info_) {
+    io_thread_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&mojo::embedder::DestroyChannelOnIOThread, channel_info_));
+  }
+}
+
+void MojoChannelInit::Init(
+    base::PlatformFile file,
+    scoped_refptr<base::TaskRunner> io_thread_task_runner) {
+  DCHECK(io_thread_task_runner_.get() == NULL);  // Should only init once.

[viettrungluu, 2014/03/13 23:02:36]

Note: I imagine that even if we remove the scoped_refptr's implicit conversion
to a dumb pointer, we'll keep it testable (like scoped_ptr is), so you should be
able to do just |DCHECK(!io_thread_task_runner_);|.

[sky, 2014/03/13 23:14:48]

Done.

+  io_thread_task_runner_ = io_thread_task_runner;
+  InitMojo();
+  handle_.reset(
+      mojo::Handle(
+          mojo::embedder::CreateChannel(
+              mojo::embedder::ScopedPlatformHandle(
+                  mojo::embedder::PlatformHandle(file)),
+              io_thread_task_runner,
+              base::Bind(&MojoChannelInit::OnCreatedChannelOnIOThread,
+                         weak_factory_.GetWeakPtr(),
+                         main_thread_,
+                         io_thread_task_runner))));
+}
+
+// static
+void MojoChannelInit::OnCreatedChannelOnIOThread(
+    base::WeakPtr<MojoChannelInit> host,
+    scoped_refptr<base::TaskRunner> main_thread,
+    scoped_refptr<base::TaskRunner> io_thread,
+    mojo::embedder::ChannelInfo* channel) {
+  main_thread->PostTask(
+      FROM_HERE,
+      base::Bind(&MojoChannelInit::OnCreatedChannelOnMainThread, host,
+                 io_thread, channel));
+}
+
+// static
+void MojoChannelInit::OnCreatedChannelOnMainThread(
+    base::WeakPtr<MojoChannelInit> host,
+    scoped_refptr<base::TaskRunner> io_thread,
+    mojo::embedder::ChannelInfo* channel) {
+  // By the time we get here |host| may have been destroyed. If so, shutdown the
+  // channel.
+  if (!host.get()) {
+    io_thread->PostTask(
+        FROM_HERE,
+        base::Bind(&mojo::embedder::DestroyChannelOnIOThread, channel));
+    return;
+  }
+  host->channel_info_ = channel;
+}
+
+
+}  // namespace content