Frame Timing tracker for http://w3c.github.io/frame-timing/

New classes:

* FrameTimingTracker - class to collect CompositeEvents from LayerTreeHostImpl and buffer them up until LayerTreeHost can request them and forward them to Blink.

* FrameTimingTracker::CompositeTimingEvent - helper class to store the information about a give Composite event. This currently includes the Main Frame # that generated the event, and the timestamp corresponding to the requestAnimationFrame beginTime. In the future it may be extended to include more detailed timing information about the cost of producing this frame.

BUG=441555

Review URL: https://codereview.chromium.org/848693003

Cr-Commit-Position: refs/heads/master@{#312002}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 67aabfd..746cf75 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -78,6 +78,8 @@
     "debug/devtools_instrumentation.h",
     "debug/frame_rate_counter.cc",
     "debug/frame_rate_counter.h",
+    "debug/frame_timing_tracker.cc",
+    "debug/frame_timing_tracker.h",
     "debug/frame_viewer_instrumentation.cc",
     "debug/frame_viewer_instrumentation.h",
     "debug/invalidation_benchmark.cc",
@@ -739,6 +741,7 @@
     "base/simple_enclosed_region_unittest.cc",
     "base/tiling_data_unittest.cc",
     "base/util_unittest.cc",
+    "debug/frame_timing_tracker_unittest.cc",
     "debug/micro_benchmark_controller_unittest.cc",
     "input/top_controls_manager_unittest.cc",
     "layers/contents_scaling_layer_unittest.cc",