cc:: Add remote mode to the compositor

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 70740935217a4482d62abd598cb54e879017a7d4..5a0c720c5c3ecf786c22c0ee6d493d096f595008 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -46,6 +46,7 @@
 #include "cc/trees/layer_tree_host_impl.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/proxy_main.h"
+#include "cc/trees/remote_channel_impl.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/tree_synchronizer.h"
 #include "ui/gfx/geometry/size_conversions.h"
@@ -89,6 +90,45 @@ scoped_ptr<LayerTreeHost> LayerTreeHost::CreateSingleThreaded(
   return layer_tree_host;
 }
 
+scoped_ptr<LayerTreeHost> LayerTreeHost::CreateRemoteServer(
+    RemoteProtoChannel* remote_proto_channel,
+    InitParams* params) {
+  DCHECK(params->main_task_runner.get());
+  DCHECK(params->settings);
+  DCHECK(remote_proto_channel);
+
+  // Using an external begin frame source is not supported in remote mode.

[vmpstr, 2016/01/11 21:50:15]

... in remote server mode.

[Khushal, 2016/01/13 02:07:12]

Done.

+  DCHECK(!params->settings->use_external_begin_frame_source);
+  DCHECK(!params->external_begin_frame_source);
+
+  scoped_ptr<LayerTreeHost> layer_tree_host(
+      new LayerTreeHost(params, CompositorMode::Remote));
+  layer_tree_host->InitializeRemoteServer(remote_proto_channel,
+                                          params->main_task_runner);
+  return layer_tree_host;
+}
+
+scoped_ptr<LayerTreeHost> LayerTreeHost::CreateRemoteClient(
+    RemoteProtoChannel* remote_proto_channel,
+    scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner,
+    InitParams* params) {
+  DCHECK(params->main_task_runner.get());
+  DCHECK(params->settings);
+  DCHECK(remote_proto_channel);
+
+  // Using an external begin frame source is not supported in remote mode.
+  // TODO(khushalsagar): Add support for providing an external begin frame

[vmpstr, 2016/01/11 21:50:15]

File a bug for this and reference it in here, please.

[Khushal, 2016/01/13 02:07:12]

Done.

+  // source on the client LayerTreeHost.
+  DCHECK(!params->settings->use_external_begin_frame_source);
+  DCHECK(!params->external_begin_frame_source);
+
+  scoped_ptr<LayerTreeHost> layer_tree_host(
+      new LayerTreeHost(params, CompositorMode::Remote));
+  layer_tree_host->InitializeRemoteClient(
+      remote_proto_channel, params->main_task_runner, impl_task_runner);
+  return layer_tree_host;
+}
+
 LayerTreeHost::LayerTreeHost(InitParams* params, CompositorMode mode)
     : micro_benchmark_controller_(this),
       next_ui_resource_id_(1),
@@ -162,6 +202,26 @@ void LayerTreeHost::InitializeSingleThreaded(
                   std::move(external_begin_frame_source));
 }
 
+void LayerTreeHost::InitializeRemoteServer(
+    RemoteProtoChannel* remote_proto_channel,
+    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner) {
+  task_runner_provider_ = TaskRunnerProvider::Create(main_task_runner, nullptr);
+  InitializeProxy(ProxyMain::CreateRemote(remote_proto_channel, this,
+                                          task_runner_provider_.get()),
+                  nullptr);
+}
+
+void LayerTreeHost::InitializeRemoteClient(
+    RemoteProtoChannel* remote_proto_channel,
+    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
+  task_runner_provider_ =
+      TaskRunnerProvider::Create(main_task_runner, impl_task_runner);
+  InitializeProxy(RemoteChannelImpl::Create(this, remote_proto_channel,

[vmpstr, 2016/01/11 21:50:15]

I think it's worth putting a comment here to kind of explain the overall
structure of the client

LTH owns RCI which owns foo

[Khushal, 2016/01/13 02:07:12]

Done.

+                                            task_runner_provider_.get()),
+                  nullptr);
+}
+
 void LayerTreeHost::InitializeForTesting(
     scoped_ptr<TaskRunnerProvider> task_runner_provider,
     scoped_ptr<Proxy> proxy_for_testing,
@@ -181,6 +241,7 @@ void LayerTreeHost::InitializeProxy(
     scoped_ptr<Proxy> proxy,
     scoped_ptr<BeginFrameSource> external_begin_frame_source) {
   TRACE_EVENT0("cc", "LayerTreeHost::InitializeForReal");
+  DCHECK(task_runner_provider_);
 
   proxy_ = std::move(proxy);
   proxy_->Start(std::move(external_begin_frame_source));
@@ -226,6 +287,20 @@ LayerTreeHost::~LayerTreeHost() {
   }
 }
 
+void LayerTreeHost::ToProtobuf() {
+  DCHECK(task_runner_provider_->IsMainThread());
+  DCHECK(IsRemoteServer());
+
+  // TODO(khushalsagar, nyquist): Serialize LayerTreeHost state to proto.

[vmpstr, 2016/01/11 21:50:15]

crbug?

[Khushal, 2016/01/13 02:07:12]

Removed.

+}
+
+void LayerTreeHost::FromProtobuf() {
+  DCHECK(task_runner_provider_->IsMainThread());
+  DCHECK(IsRemoteClient());
+
+  // TODO(khushalsagar, nyquist): Deserialize LayerTreeHost state from proto.

[vmpstr, 2016/01/11 21:50:15]

crbug?

[Khushal, 2016/01/13 02:07:12]

Removed.

+}
+
 void LayerTreeHost::WillBeginMainFrame() {
   devtools_instrumentation::WillBeginMainThreadFrame(id(),
                                                      source_frame_number());
@@ -258,6 +333,7 @@ void LayerTreeHost::RequestMainFrameUpdate() {
 // should be delayed until the LayerTreeHost::CommitComplete, which will run
 // after the commit, but on the main thread.
 void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
+  DCHECK(!IsRemoteServer());
   DCHECK(task_runner_provider_->IsImplThread());
 
   bool is_new_trace;
@@ -443,6 +519,7 @@ void LayerTreeHost::DidFailToInitializeOutputSurface() {
 
 scoped_ptr<LayerTreeHostImpl> LayerTreeHost::CreateLayerTreeHostImpl(
     LayerTreeHostImplClient* client) {
+  DCHECK(!IsRemoteServer());
   DCHECK(task_runner_provider_->IsImplThread());
   scoped_ptr<LayerTreeHostImpl> host_impl = LayerTreeHostImpl::Create(
       settings_, client, task_runner_provider_.get(),
@@ -912,8 +989,8 @@ void LayerTreeHost::SetPaintedDeviceScaleFactor(
 void LayerTreeHost::UpdateTopControlsState(TopControlsState constraints,
                                            TopControlsState current,
                                            bool animate) {
-  // Top controls are only used in threaded mode.
-  DCHECK(IsThreaded());
+  // Top controls are only used in threaded or remote mode.
+  DCHECK(IsThreaded() || IsRemoteServer());
   proxy_->UpdateTopControlsState(constraints, current, animate);
 }
 
@@ -1276,4 +1353,15 @@ bool LayerTreeHost::IsThreaded() const {
   return compositor_mode_ == CompositorMode::Threaded;
 }
 
+bool LayerTreeHost::IsRemoteServer() const {
+  // The LayerTreeHost on the server does not have an impl task runner.
+  return compositor_mode_ == CompositorMode::Remote &&
+         !task_runner_provider_->HasImplThread();
+}
+
+bool LayerTreeHost::IsRemoteClient() const {
+  return compositor_mode_ == CompositorMode::Remote &&
+         task_runner_provider_->HasImplThread();
+}
+
 }  // namespace cc