cc:: Add remote mode to the compositor

cc/trees/proxy_main.cc

Index: cc/trees/proxy_main.cc
diff --git a/cc/trees/proxy_main.cc b/cc/trees/proxy_main.cc
index 1b06367eb0abc6a35204c863170d1841cdb860db..5a61dd7eb2848fbade27803311e18ff990c806ee 100644
--- a/cc/trees/proxy_main.cc
+++ b/cc/trees/proxy_main.cc
@@ -16,6 +16,7 @@
 #include "cc/output/swap_promise.h"
 #include "cc/trees/blocking_task_runner.h"
 #include "cc/trees/layer_tree_host.h"
+#include "cc/trees/remote_channel_main.h"
 #include "cc/trees/scoped_abort_remaining_swap_promises.h"
 #include "cc/trees/threaded_channel.h"
 
@@ -31,6 +32,17 @@ scoped_ptr<ProxyMain> ProxyMain::CreateThreaded(
   return proxy_main;
 }
 
+scoped_ptr<ProxyMain> ProxyMain::CreateRemote(
+    RemoteProtoChannel* remote_proto_channel,
+    LayerTreeHost* layer_tree_host,
+    TaskRunnerProvider* task_runner_provider) {
+  scoped_ptr<ProxyMain> proxy_main(
+      new ProxyMain(layer_tree_host, task_runner_provider));
+  proxy_main->SetChannel(RemoteChannelMain::Create(
+      remote_proto_channel, proxy_main.get(), task_runner_provider));
+  return proxy_main;
+}
+
 ProxyMain::ProxyMain(LayerTreeHost* layer_tree_host,
                      TaskRunnerProvider* task_runner_provider)
     : layer_tree_host_(layer_tree_host),
@@ -377,7 +389,6 @@ void ProxyMain::MainThreadHasStoppedFlinging() {
 void ProxyMain::Start(
     scoped_ptr<BeginFrameSource> external_begin_frame_source) {
   DCHECK(IsMainThread());
-  DCHECK(task_runner_provider_->HasImplThread());

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

Should this be 

DCHECK(!external_begin_frame_source || task_runner_provider_->HasImplThread()) 

instead?

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

If the client does not use the external begin frame source then we'll not have
this DCHECK.
We could either make the IsThreaded() or IsRemoteServer() methods public on the
LayerTreeHost?

[ericrk, 2016/01/20 22:32:28]

Seems like we could use IsRemoteServer a few places - I'm not too opposed to
making this public.

[Khushal, 2016/01/22 01:03:24]

Done.

   DCHECK(channel_main_);
   DCHECK(!layer_tree_host_->settings().use_external_begin_frame_source ||
          external_begin_frame_source);