WIP: Plumbing input event latency reporting through Mus GPU.

cc/surfaces/surface_factory.cc

Index: cc/surfaces/surface_factory.cc
diff --git a/cc/surfaces/surface_factory.cc b/cc/surfaces/surface_factory.cc
index 880cb8c828a675fe85cd426bfb9caa05355e6cbc..c92bda0c8081bb9c9bd0bcd51da38652418ad63e 100644
--- a/cc/surfaces/surface_factory.cc
+++ b/cc/surfaces/surface_factory.cc
@@ -47,6 +47,20 @@ void SurfaceFactory::SubmitCompositorFrame(
     const DrawCallback& callback) {
   TRACE_EVENT0("cc", "SurfaceFactory::SubmitCompositorFrame");
   DCHECK(local_surface_id.is_valid());
+
+  for (ui::LatencyInfo& latency : frame.metadata.latency_info) {
+    // TODO: These latencies need to be saved somehow.
+    // TODO: Rename INPUT_EVENT_BROWSER_RECEIVED_RENDERER_SWAP_COMPONENT
+    // TODO: Remove similar code in RWHLatencyTracker?
+    // TODO: Better if? Maybe just check if latency_info has ANY components?
+    if (latency.FindLatency(ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT, nullptr) ||
+        latency.FindLatency(ui::WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT, nullptr) ||
+        latency.FindLatency(ui::TAB_SHOW_COMPONENT, nullptr)) {
+      latency.AddLatencyNumber(
+          ui::INPUT_EVENT_BROWSER_RECEIVED_RENDERER_SWAP_COMPONENT, 0, 0);
+    }
+  }
+
   std::unique_ptr<Surface> surface;
   bool create_new_surface =
       (!current_surface_ ||