Surfaces system timestamp in the blink platform interface.

content/child/blink_platform_impl.h

 // Copyright 2014 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 CONTENT_CHILD_BLINK_PLATFORM_IMPL_H_
 #define CONTENT_CHILD_BLINK_PLATFORM_IMPL_H_
 
 #include "base/compiler_specific.h"
 #include "base/threading/thread_local_storage.h"
 #include "base/timer/timer.h"
@@ skipping 126 matching lines @@
   virtual blink::WebString queryLocalizedString(
       blink::WebLocalizedString::Name name, int numeric_value);
   virtual blink::WebString queryLocalizedString(
       blink::WebLocalizedString::Name name, const blink::WebString& value);
   virtual blink::WebString queryLocalizedString(
       blink::WebLocalizedString::Name name,
       const blink::WebString& value1, const blink::WebString& value2);
   virtual void suddenTerminationChanged(bool enabled) { }
   virtual double currentTime();
   virtual double monotonicallyIncreasingTime();
+  virtual double systemTraceTime();
   virtual void cryptographicallyRandomValues(
       unsigned char* buffer, size_t length);
   virtual void setSharedTimerFiredFunction(void (*func)());
   virtual void setSharedTimerFireInterval(double interval_seconds);
   virtual void stopSharedTimer();
   virtual void callOnMainThread(void (*func)(void*), void* context);
   virtual blink::WebGestureCurve* createFlingAnimationCurve(
       blink::WebGestureDevice device_source,
       const blink::WebFloatPoint& velocity,
       const blink::WebSize& cumulative_scroll);
@@ skipping 44 matching lines @@
 
   scoped_refptr<ThreadSafeSender> thread_safe_sender_;
   scoped_refptr<NotificationDispatcher> notification_dispatcher_;
   scoped_refptr<PushDispatcher> push_dispatcher_;
   scoped_ptr<PermissionDispatcher> permission_client_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_BLINK_PLATFORM_IMPL_H_