Add UMA metrics for measuring number of coalesed events and their latency.

ui/base/events/event_utils.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_EVENTS_EVENT_UTILS_H_
 #define UI_BASE_EVENTS_EVENT_UTILS_H_
 
 #include "base/event_types.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/base/keycodes/keyboard_codes.h"
@@ skipping 50 matching lines @@
 UI_EXPORT int EventButtonFromNative(const base::NativeEvent& native_event);
 #endif
 
 // Returns the KeyboardCode from a native event.
 UI_EXPORT KeyboardCode KeyboardCodeFromNative(
     const base::NativeEvent& native_event);
 
 // Returns true if the message is a mouse event.
 UI_EXPORT bool IsMouseEvent(const base::NativeEvent& native_event);
 
+// Returns true if |type| is a Key event type.
+UI_EXPORT bool IsKeyEventType(EventType type);
+
+// Returns true if |type| is a Mouse event type.
+UI_EXPORT bool IsMouseEventType(EventType type);
+
+// Returns true if |type| is a Touch event type.
+UI_EXPORT bool IsTouchEventType(EventType type);
+
 // Returns the flags of the button that changed during a press/release.
 UI_EXPORT int GetChangedMouseButtonFlagsFromNative(
     const base::NativeEvent& native_event);
 
 // Gets the mouse wheel offset from a native event.
 UI_EXPORT int GetMouseWheelOffset(const base::NativeEvent& native_event);
 
 // Gets the touch id from a native event.
 UI_EXPORT int GetTouchId(const base::NativeEvent& native_event);
 
@@ skipping 58 matching lines @@
 // Returns true if default post-target handling was canceled for |event| after
 // its dispatch to its target.
 UI_EXPORT bool EventCanceledDefaultHandling(const Event& event);
 
 // Registers a custom event type.
 UI_EXPORT int RegisterCustomEventType();
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENTS_EVENT_UTILS_H_