[Reland] Optimize blink scheduler with an intrusive heap

third_party/WebKit/Source/platform/scheduler/renderer/auto_advancing_virtual_time_domain.cc

Index: third_party/WebKit/Source/platform/scheduler/renderer/auto_advancing_virtual_time_domain.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/auto_advancing_virtual_time_domain.cc b/third_party/WebKit/Source/platform/scheduler/renderer/auto_advancing_virtual_time_domain.cc
index 06e075864af63bf7989df54d9c32a5b589eb0688..a34edb2157bf0e6b65be050ff4a205073bff97b0 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/auto_advancing_virtual_time_domain.cc
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/auto_advancing_virtual_time_domain.cc
@@ -25,8 +25,9 @@ bool AutoAdvancingVirtualTimeDomain::MaybeAdvanceTime() {
 
 void AutoAdvancingVirtualTimeDomain::RequestWakeup(base::TimeTicks now,
                                                    base::TimeDelta delay) {
-  base::TimeTicks dummy;
-  if (can_advance_virtual_time_ && !NextScheduledRunTime(&dummy))
+  // Avoid posting pointless DoWorks.  I.e. if the time domain has more then one
+  // scheduled wake up then we don't need to do anything.
+  if (can_advance_virtual_time_ && NumberOfScheduledWakeups() == 1u)
     RequestDoWork();
 }