Update VideoFramePump to pass un-changed frames to encoders.

remoting/host/client_session.cc

Index: remoting/host/client_session.cc
diff --git a/remoting/host/client_session.cc b/remoting/host/client_session.cc
index d6a02fa64e5c4877b33fbb7bce16342630398590..2b72eca8c7bac1f7cb543161367d20aebe8d87bc 100644
--- a/remoting/host/client_session.cc
+++ b/remoting/host/client_session.cc
@@ -6,6 +6,7 @@
 
 #include <algorithm>
 
+#include "base/command_line.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "remoting/base/capabilities.h"
@@ -41,6 +42,9 @@ namespace remoting {
 
 namespace {
 
+// Name of command-line flag to enable VP9 to use I444 by default.
+const char kEnableI444SwitchName[] = "enable-i444";
+
 scoped_ptr<VideoEncoder> CreateVideoEncoder(
     const protocol::SessionConfig& config) {
   const protocol::ChannelConfig& video_config = config.video_config();
@@ -107,7 +111,8 @@ ClientSession::ClientSession(
       is_authenticated_(false),
       pause_video_(false),
       lossless_video_encode_(false),
-      lossless_video_color_(false),
+      lossless_video_color_(base::CommandLine::ForCurrentProcess()->HasSwitch(
+          kEnableI444SwitchName)),
       weak_factory_(this) {
   connection_->SetEventHandler(this);