Track input latency with UMA stats

ui/base/events/event.cc

Index: ui/base/events/event.cc
diff --git a/ui/base/events/event.cc b/ui/base/events/event.cc
index e24c1761aba0f6a5c15b85d1114d5f961d1abecd..e999f3334375acdb3ea16b1a62e598476e693555 100644
--- a/ui/base/events/event.cc
+++ b/ui/base/events/event.cc
@@ -11,6 +11,8 @@
 #include <cmath>
 #include <cstring>
 
+#include "base/metrics/histogram.h"
+#include "base/stringprintf.h"
 #include "ui/base/events/event_utils.h"
 #include "ui/base/keycodes/keyboard_code_conversion.h"
 #include "ui/gfx/point3_f.h"
@@ -53,47 +55,50 @@ gfx::Point CalibratePoint(const gfx::Point& point,
 
 std::string EventTypeName(ui::EventType type) {
 #define RETURN_IF_TYPE(t) if (type == ui::t)  return #t
-  RETURN_IF_TYPE(ET_UNKNOWN);
-  RETURN_IF_TYPE(ET_MOUSE_PRESSED);
-  RETURN_IF_TYPE(ET_MOUSE_DRAGGED);
-  RETURN_IF_TYPE(ET_MOUSE_RELEASED);
-  RETURN_IF_TYPE(ET_MOUSE_MOVED);
-  RETURN_IF_TYPE(ET_MOUSE_ENTERED);
-  RETURN_IF_TYPE(ET_MOUSE_EXITED);
-  RETURN_IF_TYPE(ET_KEY_PRESSED);
-  RETURN_IF_TYPE(ET_KEY_RELEASED);
-  RETURN_IF_TYPE(ET_MOUSEWHEEL);
-  RETURN_IF_TYPE(ET_MOUSE_CAPTURE_CHANGED);
-  RETURN_IF_TYPE(ET_TOUCH_RELEASED);
-  RETURN_IF_TYPE(ET_TOUCH_PRESSED);
-  RETURN_IF_TYPE(ET_TOUCH_MOVED);
-  RETURN_IF_TYPE(ET_TOUCH_STATIONARY);
-  RETURN_IF_TYPE(ET_TOUCH_CANCELLED);
-  RETURN_IF_TYPE(ET_DROP_TARGET_EVENT);
-  RETURN_IF_TYPE(ET_TRANSLATED_KEY_PRESS);
-  RETURN_IF_TYPE(ET_TRANSLATED_KEY_RELEASE);
-
-  RETURN_IF_TYPE(ET_GESTURE_SCROLL_BEGIN);
-  RETURN_IF_TYPE(ET_GESTURE_SCROLL_END);
-  RETURN_IF_TYPE(ET_GESTURE_SCROLL_UPDATE);
-  RETURN_IF_TYPE(ET_GESTURE_TAP);
-  RETURN_IF_TYPE(ET_GESTURE_TAP_DOWN);
-  RETURN_IF_TYPE(ET_GESTURE_TAP_CANCEL);
-  RETURN_IF_TYPE(ET_GESTURE_BEGIN);
-  RETURN_IF_TYPE(ET_GESTURE_END);
-  RETURN_IF_TYPE(ET_GESTURE_DOUBLE_TAP);
-  RETURN_IF_TYPE(ET_GESTURE_TWO_FINGER_TAP);
-  RETURN_IF_TYPE(ET_GESTURE_PINCH_BEGIN);
-  RETURN_IF_TYPE(ET_GESTURE_PINCH_END);
-  RETURN_IF_TYPE(ET_GESTURE_PINCH_UPDATE);
-  RETURN_IF_TYPE(ET_GESTURE_LONG_PRESS);
-  RETURN_IF_TYPE(ET_GESTURE_LONG_TAP);
-  RETURN_IF_TYPE(ET_GESTURE_MULTIFINGER_SWIPE);
-
-  RETURN_IF_TYPE(ET_SCROLL);
-  RETURN_IF_TYPE(ET_SCROLL_FLING_START);
-  RETURN_IF_TYPE(ET_SCROLL_FLING_CANCEL);
-#undef RETURN_IF_TYPE
+#define CASE_TYPE(t) case ui::t:  return #t
+  switch (type) {
+    CASE_TYPE(ET_UNKNOWN);
+    CASE_TYPE(ET_MOUSE_PRESSED);
+    CASE_TYPE(ET_MOUSE_DRAGGED);
+    CASE_TYPE(ET_MOUSE_RELEASED);
+    CASE_TYPE(ET_MOUSE_MOVED);
+    CASE_TYPE(ET_MOUSE_ENTERED);
+    CASE_TYPE(ET_MOUSE_EXITED);
+    CASE_TYPE(ET_KEY_PRESSED);
+    CASE_TYPE(ET_KEY_RELEASED);
+    CASE_TYPE(ET_MOUSEWHEEL);
+    CASE_TYPE(ET_MOUSE_CAPTURE_CHANGED);
+    CASE_TYPE(ET_TOUCH_RELEASED);
+    CASE_TYPE(ET_TOUCH_PRESSED);
+    CASE_TYPE(ET_TOUCH_MOVED);
+    CASE_TYPE(ET_TOUCH_STATIONARY);
+    CASE_TYPE(ET_TOUCH_CANCELLED);
+    CASE_TYPE(ET_DROP_TARGET_EVENT);
+    CASE_TYPE(ET_TRANSLATED_KEY_PRESS);
+    CASE_TYPE(ET_TRANSLATED_KEY_RELEASE);
+    CASE_TYPE(ET_GESTURE_SCROLL_BEGIN);
+    CASE_TYPE(ET_GESTURE_SCROLL_END);
+    CASE_TYPE(ET_GESTURE_SCROLL_UPDATE);
+    CASE_TYPE(ET_GESTURE_TAP);
+    CASE_TYPE(ET_GESTURE_TAP_DOWN);
+    CASE_TYPE(ET_GESTURE_TAP_CANCEL);
+    CASE_TYPE(ET_GESTURE_BEGIN);
+    CASE_TYPE(ET_GESTURE_END);
+    CASE_TYPE(ET_GESTURE_DOUBLE_TAP);
+    CASE_TYPE(ET_GESTURE_TWO_FINGER_TAP);
+    CASE_TYPE(ET_GESTURE_PINCH_BEGIN);
+    CASE_TYPE(ET_GESTURE_PINCH_END);
+    CASE_TYPE(ET_GESTURE_PINCH_UPDATE);
+    CASE_TYPE(ET_GESTURE_LONG_PRESS);
+    CASE_TYPE(ET_GESTURE_LONG_TAP);
+    CASE_TYPE(ET_GESTURE_MULTIFINGER_SWIPE);
+    CASE_TYPE(ET_SCROLL);
+    CASE_TYPE(ET_SCROLL_FLING_START);
+    CASE_TYPE(ET_SCROLL_FLING_CANCEL);
+    case ui::ET_LAST: NOTREACHED(); return std::string();
+    // Don't include default, so that we get an error when new type is added.
+  }
+#undef CASE_TYPE
 
   NOTREACHED();
   return std::string();
@@ -162,8 +167,21 @@ Event::Event(const base::NativeEvent& native_event,
       target_(NULL),
       phase_(EP_PREDISPATCH),
       result_(ER_UNHANDLED) {
+  base::TimeDelta delta = ui::EventTimeForNow() - time_stamp_;
   if (type_ < ET_LAST)
     name_ = EventTypeName(type_);
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Event.Latency.Browser",
+                              delta.InMicroseconds(), 0, 1000000, 100);
+  std::string name_for_event =
+      base::StringPrintf("Event.Latency.Browser.%s", name_.c_str());
+  base::Histogram* counter_for_type =
+      base::Histogram::FactoryTimeGet(
+          name_for_event,
+          base::TimeDelta::FromMilliseconds(0),
+          base::TimeDelta::FromMilliseconds(1000000),
+          100,
+          base::Histogram::kUmaTargetedHistogramFlag);
+  counter_for_type->AddTime(delta);
   InitWithNativeEvent(native_event);
 }
 
@@ -253,8 +271,11 @@ MouseEvent::MouseEvent(EventType type,
                        const gfx::Point& location,
                        const gfx::Point& root_location,
                        int flags)
-    : LocatedEvent(type, location, root_location,
-                   base::Time::NowFromSystemTime() - base::Time(), flags),
+    : LocatedEvent(type,
+                   location,
+                   root_location,
+                   ui::EventTimeForNow(),
+                   flags),
       changed_button_flags_(0) {
   if (this->type() == ET_MOUSE_MOVED && IsAnyButton())
     SetType(ET_MOUSE_DRAGGED);
@@ -455,7 +476,7 @@ KeyEvent::KeyEvent(EventType type,
                    KeyboardCode key_code,
                    int flags,
                    bool is_char)
-    : Event(type, base::Time::NowFromSystemTime() - base::Time(), flags),
+    : Event(type, EventTimeForNow(), flags),
       key_code_(key_code),
       is_char_(is_char),
       character_(GetCharacterFromKeyCode(key_code, flags)),
@@ -579,8 +600,11 @@ DropTargetEvent::DropTargetEvent(const OSExchangeData& data,
                                  const gfx::Point& location,
                                  const gfx::Point& root_location,
                                  int source_operations)
-    : LocatedEvent(ET_DROP_TARGET_EVENT, location, root_location,
-                   base::Time::NowFromSystemTime() - base::Time(), 0),
+    : LocatedEvent(ET_DROP_TARGET_EVENT,
+                   location,
+                   root_location,
+                   ui::EventTimeForNow(),
+                   0),
       data_(data),
       source_operations_(source_operations) {
 }