cc:: Add remote mode to the compositor

cc/trees/remote_channel_host.cc

Index: cc/trees/remote_channel_host.cc
diff --git a/cc/trees/remote_channel_host.cc b/cc/trees/remote_channel_host.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c4fc98bffdad6e7a1e0bb16dbc4e73b628c793bb
--- /dev/null
+++ b/cc/trees/remote_channel_host.cc
@@ -0,0 +1,114 @@
+// Copyright 2015 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 "cc/trees/remote_channel_host.h"
+
+#include "cc/proto/compositor_message.pb.h"
+#include "cc/proto/compositor_message_to_impl.pb.h"
+
+namespace cc {
+
+scoped_ptr<RemoteChannelHost> RemoteChannelHost::Create(
+    RemoteProtoChannel* remote_proto_channel,
+    RemoteChannelHostClient* client,
+    TaskGraphRunner* task_graph_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
+  return make_scoped_ptr(
+      new RemoteChannelHost(remote_proto_channel, client, task_graph_runner,
+                            main_task_runner, impl_task_runner));
+}
+
+RemoteChannelHost::RemoteChannelHost(
+    RemoteProtoChannel* remote_proto_channel,
+    RemoteChannelHostClient* client,
+    TaskGraphRunner* task_graph_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner)
+    : remote_proto_channel_(remote_proto_channel),
+      client_(client),
+      task_graph_runner_(task_graph_runner),
+      main_task_runner_(main_task_runner),
+      impl_task_runner_(impl_task_runner),
+      did_shutdown_(false) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  DCHECK(remote_proto_channel_);
+  DCHECK(client_);
+  DCHECK(task_graph_runner_);
+  remote_proto_channel_->SetProtoReceiver(this);
+}
+
+RemoteChannelHost::~RemoteChannelHost() {

[David Trainor- moved to gerrit, 2015/12/11 17:13:44]

remote_proto_channel_->SetProtoReceiver(nullptr) here?  You might have to update
your test expectation and remove that DCHECK though.  We shouldn't make any
assumptions about the RemoteProtoChannel lifecycle though.

[Khushal, 2015/12/11 22:49:37]

Done.
I was unsure about this too. But I think its safe to assume that the
RemoteProtoChannel will outlive its receivers.

Added that in the comments for that class.

+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  if (remote_channel_impl_)
+    remote_channel_impl_.reset();
+}
+
+scoped_ptr<RemoteChannelImpl> RemoteChannelHost::CreateRemoteChannelImpl(
+    RemoteChannelHost* remote_channel_host,
+    TaskGraphRunner* task_graph_runner,
+    const LayerTreeSettings& settings,
+    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
+  return RemoteChannelImpl::Create(remote_channel_host, task_graph_runner,
+                                   settings, main_task_runner,
+                                   impl_task_runner);
+}
+
+void RemoteChannelHost::SendProto(const proto::CompositorMessage& proto) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  remote_proto_channel_->SendCompositorProto(proto);
+}
+
+void RemoteChannelHost::OnProtoReceived(
+    scoped_ptr<proto::CompositorMessage> proto) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  DCHECK(!did_shutdown_);
+  DCHECK(proto->has_to_impl());
+  proto::CompositorMessageToImpl to_impl_proto = proto->to_impl();
+  switch (to_impl_proto.message_type()) {
+    case proto::CompositorMessageToImpl::Unknown:
+      return;
+    case proto::CompositorMessageToImpl::InitializeImpl:
+      InitializeImpl(to_impl_proto.initialize_impl_message());
+      return;
+    case proto::CompositorMessageToImpl::CloseImpl:
+      DCHECK(remote_channel_impl_);
+      remote_channel_impl_.reset();
+
+      did_shutdown_ = true;
+
+      // It is not safe to access any variables after this method is called. The
+      // client may destroy us now so |this| will not be there anymore.
+      client_->DidShutdown();
+      return;
+    default:
+      DCHECK(remote_channel_impl_);
+      remote_channel_impl_->HandleProto(to_impl_proto);
+  }
+}
+
+void RemoteChannelHost::InitializeImpl(const proto::InitializeImpl& proto) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  DCHECK(!remote_channel_impl_);
+  proto::LayerTreeSettings settings_proto = proto.layer_tree_settings();
+
+  // TODO(khushalsagar, nyquist): Deserialize using
+  // LayerTreeSettings:FromProtobuf.
+  LayerTreeSettings settings;
+  settings.single_thread_proxy_scheduler =
+      settings_proto.single_thread_proxy_scheduler();
+
+  client_->OverrideLayerTreeSettings(&settings);
+
+  remote_channel_impl_ = CreateRemoteChannelImpl(
+      this, task_graph_runner_, settings, main_task_runner_, impl_task_runner_);
+  remote_channel_impl_->Initialize();
+
+  task_graph_runner_ = nullptr;
+  main_task_runner_ = nullptr;
+  impl_task_runner_ = nullptr;
+}
+
+}  // namespace cc