Expand UMA coverage for compositor-handled events and fling FPS

content/renderer/input/input_handler_proxy.cc

Index: content/renderer/input/input_handler_proxy.cc
diff --git a/content/renderer/input/input_handler_proxy.cc b/content/renderer/input/input_handler_proxy.cc
index 0d4b17320a1986903d7c6942d404731474f9c534..ce178ec13ec1a6ae1f416291df6f62d0cae9dfbf 100644
--- a/content/renderer/input/input_handler_proxy.cc
+++ b/content/renderer/input/input_handler_proxy.cc
@@ -115,11 +115,15 @@ WebGestureEvent ObtainGestureScrollBegin(const WebGestureEvent& event) {
   return scroll_begin_event;
 }
 
-void SendScrollLatencyUma(const WebInputEvent& event,
-                          const ui::LatencyInfo& latency_info) {
+void ReportInputEventLatencyUma(const WebInputEvent& event,
+                                const ui::LatencyInfo& latency_info) {

[no sievers, 2014/12/05 21:27:00]

DCHECK(uma_latency_reporting_enabled_);

[jdduke (slow), 2014/12/05 21:31:53]

Hmm, this isn't a member function, though I could make it one if you prefer?

[no sievers, 2014/12/05 21:33:52]

Oops nevermind, no big deal.

   if (!(event.type == WebInputEvent::GestureScrollBegin ||
-        event.type == WebInputEvent::GestureScrollUpdate))
+        event.type == WebInputEvent::GestureScrollUpdate ||
+        event.type == WebInputEvent::GesturePinchBegin ||
+        event.type == WebInputEvent::GesturePinchUpdate ||
+        event.type == WebInputEvent::GestureFlingStart)) {
     return;
+  }
 
   ui::LatencyInfo::LatencyMap::const_iterator it =
       latency_info.latency_components.find(std::make_pair(
@@ -130,17 +134,42 @@ void SendScrollLatencyUma(const WebInputEvent& event,
 
   base::TimeDelta delta = base::TimeTicks::HighResNow() - it->second.event_time;
   for (size_t i = 0; i < it->second.event_count; ++i) {
-    UMA_HISTOGRAM_CUSTOM_COUNTS(
-        "Event.Latency.RendererImpl.GestureScroll2",
-        delta.InMicroseconds(),
-        1,
-        1000000,
-        100);
+    switch (event.type) {
+      case blink::WebInputEvent::GestureScrollBegin:
+        UMA_HISTOGRAM_CUSTOM_COUNTS(
+            "Event.Latency.RendererImpl.GestureScrollBegin",
+            delta.InMicroseconds(), 1, 1000000, 100);
+        break;
+      case blink::WebInputEvent::GestureScrollUpdate:
+        UMA_HISTOGRAM_CUSTOM_COUNTS(
+            // So named for historical reasons.
+            "Event.Latency.RendererImpl.GestureScroll2",
+            delta.InMicroseconds(), 1, 1000000, 100);
+        break;
+      case blink::WebInputEvent::GesturePinchBegin:
+        UMA_HISTOGRAM_CUSTOM_COUNTS(
+            "Event.Latency.RendererImpl.GesturePinchBegin",
+            delta.InMicroseconds(), 1, 1000000, 100);
+        break;
+      case blink::WebInputEvent::GesturePinchUpdate:
+        UMA_HISTOGRAM_CUSTOM_COUNTS(
+            "Event.Latency.RendererImpl.GesturePinchUpdate",
+            delta.InMicroseconds(), 1, 1000000, 100);
+        break;
+      case blink::WebInputEvent::GestureFlingStart:
+        UMA_HISTOGRAM_CUSTOM_COUNTS(
+            "Event.Latency.RendererImpl.GestureFlingStart",
+            delta.InMicroseconds(), 1, 1000000, 100);
+        break;
+      default:
+        NOTREACHED();
+        break;
+    }
   }
-}  // namespace
-
 }
 
+}  // namespace
+
 namespace content {
 
 InputHandlerProxy::InputHandlerProxy(cc::InputHandler* input_handler,
@@ -156,7 +185,9 @@ InputHandlerProxy::InputHandlerProxy(cc::InputHandler* input_handler,
       fling_may_be_active_on_main_thread_(false),
       disallow_horizontal_fling_scroll_(false),
       disallow_vertical_fling_scroll_(false),
-      has_fling_animation_started_(false) {
+      has_fling_animation_started_(false),
+      uma_latency_reporting_enabled_(
+          base::TimeTicks::IsHighResNowFastAndReliable()) {
   DCHECK(client);
   input_handler_->BindToClient(this);
   smooth_scroll_enabled_ = CommandLine::ForCurrentProcess()->HasSwitch(
@@ -185,7 +216,8 @@ InputHandlerProxy::HandleInputEventWithLatencyInfo(
     ui::LatencyInfo* latency_info) {
   DCHECK(input_handler_);
 
-  SendScrollLatencyUma(event, *latency_info);
+  if (uma_latency_reporting_enabled_)
+    ReportInputEventLatencyUma(event, *latency_info);
 
   TRACE_EVENT_FLOW_STEP0("input",
                          "LatencyInfo.Flow",