Bug 1627741: Expect an idle token only if we're actually using cross-process idle scheduling. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D69846

--HG--
extra : moz-landing-system : lando

xpcom/threads/IdlePeriodState.cpp

@@ -148,9 +148,10 @@ TimeStamp IdlePeriodState::GetIdleToken(TimeStamp aLocalIdlePeriodHint,
   MOZ_ASSERT(NS_IsMainThread(),
              "Why are we touching idle state off the main thread?");
 
-  if (XRE_IsParentProcess()) {
+  if (!ShouldGetIdleToken()) {
     return aLocalIdlePeriodHint;
   }
+
   if (mIdleToken) {
     TimeStamp now = TimeStamp::Now();
     if (mIdleToken < now) {
@@ -170,8 +171,7 @@ void IdlePeriodState::RequestIdleToken(TimeStamp aLocalIdlePeriodHint) {
 
   if (!mIdleSchedulerInitialized) {
     mIdleSchedulerInitialized = true;
-    if (StaticPrefs::idle_period_cross_process_scheduling() &&
-        XRE_IsContentProcess()) {
+    if (ShouldGetIdleToken()) {
       // For now cross-process idle scheduler is supported only on the main
       // threads of the child processes.
       mIdleScheduler = ipc::IdleSchedulerChild::GetMainThreadIdleScheduler();
@@ -244,4 +244,8 @@ void IdlePeriodState::ClearIdleToken() {
   }
 }
 
+bool IdlePeriodState::ShouldGetIdleToken() {
+  return StaticPrefs::idle_period_cross_process_scheduling() &&
+         XRE_IsContentProcess();
+}
 }  // namespace mozilla

xpcom/threads/IdlePeriodState.h

@@ -144,6 +144,10 @@ class IdlePeriodState {
   TimeStamp GetIdleDeadlineInternal(bool aIsPeek,
                                     const MutexAutoUnlock& aProofOfUnlock);
 
+  // Whether we should be getting an idle token (i.e. are a content process
+  // and are using cross process idle scheduling).
+  bool ShouldGetIdleToken();
+
   // Set to true if we have claimed we have a ready-to-run idle task when asked.
   // In that case, we will ensure that we allow at least one task to run when
   // someone tries to run a task, even if we have run out of idle period at that