Validate that ui::Event::time_stamp comes from the same clock as TimeTicks::Now

ui/events/base_event_utils.h

 // Copyright 2015 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_EVENTS_BASE_EVENT_UTILS_H_
 #define UI_EVENTS_BASE_EVENT_UTILS_H_
 
+#include <memory>
 #include <stdint.h>
 
+#include "base/time/tick_clock.h"
 #include "ui/events/events_base_export.h"
 
 namespace base {
 class TimeTicks;
 }
 
 // Common functions to be used for all platforms.
 namespace ui {
 
 // Generate an unique identifier for events.
 EVENTS_BASE_EXPORT uint32_t GetNextTouchEventId();
 
 // Checks if |flags| contains system key modifiers.
 EVENTS_BASE_EXPORT bool IsSystemKeyModifier(int flags);
 
+// Create a timestamp based on the current time.
+EVENTS_BASE_EXPORT base::TimeTicks EventTimeForNow();
+
+EVENTS_BASE_EXPORT void SetEventTickClockForTesting(
+    std::unique_ptr<base::TickClock> tick_clock);
+
 // Converts an event timestamp ticks to seconds (floating point representation).
 // WARNING: This should only be used when interfacing with platform code that
 // does not use base::Time* types.
 EVENTS_BASE_EXPORT double EventTimeStampToSeconds(base::TimeTicks time_stamp);
 
 // Converts an event timestamp in seconds to TimeTicks.
 // WARNING: This should only be used when interfacing with platform code that
 // does not use base::Time* types.
 EVENTS_BASE_EXPORT base::TimeTicks EventTimeStampFromSeconds(
     double time_stamp_seconds);
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_BASE_EVENT_UTILS_H_