[Reland] Per WebViewScheduler virtual time

third_party/WebKit/public/platform/WebTaskRunner.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 WebTaskRunner_h
 #define WebTaskRunner_h
 
 #include "WebCommon.h"
 
 #ifdef INSIDE_BLINK
@@ skipping 19 matching lines @@
     // Takes ownership of |Task|. Can be called from any thread.
     virtual void postTask(const WebTraceLocation&, Task*) = 0;
 
     // Schedule a task to be run after |delayMs| on the the associated WebThread.
     // Takes ownership of |Task|. Can be called from any thread.
     virtual void postDelayedTask(const WebTraceLocation&, Task*, double delayMs) = 0;
 
     // Returns a clone of the WebTaskRunner.
     virtual WebTaskRunner* clone() = 0;
 
+    // ---
+
+    // Headless Chrome virtualises time for determinism and performance (fast forwarding
+    // of timers). To make this work some parts of blink (e.g. Timers) need to use virtual
+    // time, however by default new code should use the normal non-virtual time APIs.
+
+    // Returns a double which is the number of seconds since epoch (Jan 1, 1970).
+    // This may represent either the real time, or a virtual time depending on
+    // whether or not the WebTaskRunner is associated with a virtual time domain or a
+    // real time domain.
+    virtual double virtualTimeSeconds() const = 0;
+
+    // Returns a microsecond resolution platform dependant time source.
+    // This may represent either the real time, or a virtual time depending on
+    // whether or not the WebTaskRunner is associated with a virtual time domain or a
+    // real time domain.
+    virtual double monotonicallyIncreasingVirtualTimeSeconds() const = 0;
+
 #ifdef INSIDE_BLINK
     // Helpers for posting bound functions as tasks.
     typedef Function<void()> ClosureTask;
 
     void postTask(const WebTraceLocation&, PassOwnPtr<ClosureTask>);
     // TODO(alexclarke): Remove this when possible.
     void postDelayedTask(const WebTraceLocation&, PassOwnPtr<ClosureTask>, long long delayMs);
     void postDelayedTask(const WebTraceLocation&, PassOwnPtr<ClosureTask>, double delayMs);
 
     PassOwnPtr<WebTaskRunner> adoptClone()
     {
         return adoptPtr(clone());
     }
 #endif
 };
 
 } // namespace blink
 
 #endif // WebTaskRunner_h