[Reland] Per WebViewScheduler virtual time

third_party/WebKit/public/platform/Platform.h

Index: third_party/WebKit/public/platform/Platform.h
diff --git a/third_party/WebKit/public/platform/Platform.h b/third_party/WebKit/public/platform/Platform.h
index 784aa7eb0fb74ccdaaffcba5f33e85c7d258468d..3ba04142cee8482c92c63ba502566c29ab564e8c 100644
--- a/third_party/WebKit/public/platform/Platform.h
+++ b/third_party/WebKit/public/platform/Platform.h
@@ -420,6 +420,12 @@ public:
     // 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 currentTimeSeconds(); }
+    virtual double monotonicallyIncreasingVirtualTimeSeconds() { return monotonicallyIncreasingTimeSeconds(); }
+
     // 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;