Bug 1678416 - Remove a couple of calls to TimeStamp::Now() r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D90900

dom/base/CCGCScheduler.h

@@ -182,18 +182,19 @@ class CCGCScheduler {
 
   // Scheduling
 
-  TimeDuration ComputeInterSliceGCBudget(TimeStamp aDeadline) const {
+  TimeDuration ComputeInterSliceGCBudget(TimeStamp aDeadline,
+                                         TimeStamp aNow) const {
     // We use longer budgets when the CC has been locked out but the CC has
     // tried to run since that means we may have a significant amount of
     // garbage to collect and it's better to GC in several longer slices than
     // in a very long one.
-    TimeDuration budget = aDeadline.IsNull() ? mActiveIntersliceGCBudget * 2
-                                             : aDeadline - TimeStamp::Now();
+    TimeDuration budget =
+        aDeadline.IsNull() ? mActiveIntersliceGCBudget * 2 : aDeadline - aNow;
     if (!mCCBlockStart) {
       return budget;
     }
 
-    TimeDuration blockedTime = TimeStamp::Now() - mCCBlockStart;
+    TimeDuration blockedTime = aNow - mCCBlockStart;
     TimeDuration maxSliceGCBudget = mActiveIntersliceGCBudget * 10;
     double percentOfBlockedTime =
         std::min(blockedTime / kMaxCCLockedoutTime, 1.0);

dom/base/nsJSEnvironment.cpp

@@ -1542,8 +1542,9 @@ void nsJSContext::EndCycleCollectionCallback(CycleCollectorResults& aResults) {
 // static
 bool InterSliceGCRunnerFired(TimeStamp aDeadline, void* aData) {
   MOZ_ASSERT(sScheduler.mActiveIntersliceGCBudget);
-  TimeDuration budget = sScheduler.ComputeInterSliceGCBudget(aDeadline);
   TimeStamp startTimeStamp = TimeStamp::Now();
+  TimeDuration budget =
+      sScheduler.ComputeInterSliceGCBudget(aDeadline, startTimeStamp);
   TimeDuration duration = sGCUnnotifiedTotalTime;
   uintptr_t reason = reinterpret_cast<uintptr_t>(aData);
   nsJSContext::GarbageCollectNow(