Reporting latency metrics for UI

This change is to verify the changes in latency metrics reported, and make sure there has been no other chanegs responsible for recent changes in the values of latency metrics.

TBR=jonross@chromium.org

Bug: chromium:1096661
Change-Id: Iafac9541c2b773cba52c3693c61d8cfb0c184064
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317829Reviewed-by: Behdad Bakhshinategh <behdadb@chromium.org>
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Behdad Bakhshinategh <behdadb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791538}

cc/trees/layer_tree_host_impl.cc

@@ -359,8 +359,7 @@ LayerTreeHostImpl::LayerTreeHostImpl(
       current_begin_frame_tracker_(FROM_HERE),
       compositor_frame_reporting_controller_(
           std::make_unique<CompositorFrameReportingController>(
-              /*should_report_metrics=*/!settings
-                  .single_thread_proxy_scheduler)),
+              /*should_report_metrics=*/true)),
       settings_(settings),
       is_synchronous_single_threaded_(!task_runner_provider->HasImplThread() &&
                                       !settings_.single_thread_proxy_scheduler),