Adds a flag to support "Virtual Time" to the blink scheduler

content/test/fake_renderer_scheduler.cc

Index: content/test/fake_renderer_scheduler.cc
diff --git a/content/test/fake_renderer_scheduler.cc b/content/test/fake_renderer_scheduler.cc
index a869bf0738f6cbe69c1f95bec522598ecadc24b5..30f65be8e3ac365299c899a89103b7debbb29ec0 100644
--- a/content/test/fake_renderer_scheduler.cc
+++ b/content/test/fake_renderer_scheduler.cc
@@ -118,4 +118,12 @@ void FakeRendererScheduler::ResumeTimerQueue() {
 void FakeRendererScheduler::SetTimerQueueSuspensionWhenBackgroundedEnabled(
     bool enabled) {}
 
+double FakeRendererScheduler::currentTime() const {
+  return 0.0;
+}
+
+double FakeRendererScheduler::monotonicallyIncreasingTime() const {
+  return 0.0;
+}
+
 }  // namespace content