[remoting host] Default lossless-color to false.

In ClientSession, lossless-color defaulted to true. But the actual
encoders defaulted this setting to false. Now that the lossless
flags have been plumbed through to the encoders, the default setting
has been changed from false to true.

This CL restores the default setting to false, since lossless-color
is not yet working for VP9. VP8 ignores the flags anyway, so is not
affected.

The command-line option is also removed. The lossless flags can be
controlled via VideoControl messages if needed.

Change-Id: I14637cdff74be5671aaa53ffd9f00b70302b55cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1768879
Auto-Submit: Lambros Lambrou <lambroslambrou@chromium.org>
Commit-Queue: Jamie Walch <jamiewalch@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690770}

remoting/host/client_session.cc

@@ -44,13 +44,6 @@ namespace remoting {
 
 using protocol::ActionRequest;
 
-namespace {
-
-// Name of command-line flag to disable use of I444 by default.
-const char kDisableI444SwitchName[] = "disable-i444";
-
-}  // namespace
-
 ClientSession::ClientSession(
     EventHandler* event_handler,
     std::unique_ptr<protocol::ConnectionToClient> connection,
@@ -71,11 +64,7 @@ ClientSession::ClientSession(
       disable_clipboard_filter_(clipboard_echo_filter_.host_filter()),
       client_clipboard_factory_(clipboard_echo_filter_.client_filter()),
       max_duration_(max_duration),
-      pairing_registry_(pairing_registry),
-      // Note that |lossless_video_color_| defaults to true, but actually only
-      // controls VP9 video stream color quality.
-      lossless_video_color_(!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          kDisableI444SwitchName)) {
+      pairing_registry_(pairing_registry) {
   connection_->session()->AddPlugin(&host_experiment_session_plugin_);
   connection_->SetEventHandler(this);