[Reland] Per WebViewScheduler virtual time

third_party/WebKit/public/platform/WebTaskRunner.h

Index: third_party/WebKit/public/platform/WebTaskRunner.h
diff --git a/third_party/WebKit/public/platform/WebTaskRunner.h b/third_party/WebKit/public/platform/WebTaskRunner.h
index defe4a1aedac05b2ce2dd8c4850f1455b2b3bb8d..5763817588e9e9bd9082418e5c2764b648b0d54b 100644
--- a/third_party/WebKit/public/platform/WebTaskRunner.h
+++ b/third_party/WebKit/public/platform/WebTaskRunner.h
@@ -37,6 +37,24 @@ public:
     // 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;