[Reland] Per WebViewScheduler virtual time

third_party/WebKit/public/platform/Platform.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
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     virtual WebString defaultLocale() { return WebString(); }
 
     // Wall clock time in seconds since the epoch.
     virtual double currentTimeSeconds() { return 0; }
 
     // Monotonically increasing time in seconds from an arbitrary fixed point in the past.
     // This function is expected to return at least millisecond-precision values. For this reason,
     // it is recommended that the fixed point be no further in the past than the epoch.
     virtual double monotonicallyIncreasingTimeSeconds() { return 0; }
 
+    // Virtual time is used by Headless Chrome for determinism and performance (fast forwarding
+    // of timers). New code should typically use |currentTimeSeconds| and
+    // |monotonicallyIncreasingTimeSeconds| as normal.
+    virtual double virtualTimeSeconds() { return 0; }
+    virtual double monotonicallyIncreasingVirtualTimeSeconds() { return 0; }
+
     // Returns an interface to the main thread. Can be null if blink was initialized on a thread without a message loop.
     BLINK_PLATFORM_EXPORT WebThread* mainThread() const;
 
     // Returns an interface to the compositor thread. This can be null if the
     // renderer was created with threaded rendering desabled.
     virtual WebThread* compositorThread() const { return 0; }
 
     // Vibration -----------------------------------------------------------
 
     // Starts a vibration for the given duration in milliseconds. If there is currently an active
@@ skipping 209 matching lines @@
 protected:
     BLINK_PLATFORM_EXPORT Platform();
     virtual ~Platform() { }
 
     WebThread* m_mainThread;
 };
 
 } // namespace blink
 
 #endif