Bug 1371664 P2 Make nsGlobalWindow::SetIsBackground() call new TimeoutManager::UpdateBackgroundState(). r=ehsan

dom/base/TimeoutManager.cpp

@@ -1152,6 +1152,14 @@ TimeoutManager::Thaw()
   });
 }
 
+void
+TimeoutManager::UpdateBackgroundState()
+{
+  if (!IsBackground()) {
+    ResetTimersForThrottleReduction();
+  }
+}
+
 bool
 TimeoutManager::IsTimeoutTracking(uint32_t aTimeoutId)
 {

dom/base/TimeoutManager.h

@@ -77,6 +77,10 @@ public:
   void Freeze();
   void Thaw();
 
+  // This should be called by nsGlobalWindow when the window might have moved
+  // to the background or foreground.
+  void UpdateBackgroundState();
+
   // Initialize TimeoutManager before the first time it is accessed.
   static void Initialize();
 

dom/base/nsGlobalWindow.cpp

@@ -10671,13 +10671,16 @@ void nsGlobalWindow::SetIsBackground(bool aIsBackground)
 {
   MOZ_ASSERT(IsOuterWindow());
 
-  bool resetTimers = (!aIsBackground && AsOuter()->IsBackground());
+  bool changed = aIsBackground != AsOuter()->IsBackground();
   SetIsBackgroundInternal(aIsBackground);
 
   nsGlobalWindow* inner = GetCurrentInnerWindowInternal();
 
+  if (inner && changed) {
+    inner->mTimeoutManager->UpdateBackgroundState();
+  }
+
   if (aIsBackground) {
-    MOZ_ASSERT(!resetTimers);
     // Notify gamepadManager we are at the background window,
     // we need to stop vibrate.
     if (inner) {
@@ -10685,9 +10688,6 @@ void nsGlobalWindow::SetIsBackground(bool aIsBackground)
     }
     return;
   } else if (inner) {
-    if (resetTimers) {
-      inner->mTimeoutManager->ResetTimersForThrottleReduction();
-    }
     inner->SyncGamepadState();
   }
 }