Revert of Move throttling of background timers into the renderer scheduler

third_party/WebKit/Source/core/frame/DOMTimer.h

Index: third_party/WebKit/Source/core/frame/DOMTimer.h
diff --git a/third_party/WebKit/Source/core/frame/DOMTimer.h b/third_party/WebKit/Source/core/frame/DOMTimer.h
index 59236c8a6ca91ca215726f03c1b2f7e1982a316f..4912ace9388b782e69082d29a668fe9568fa2d4a 100644
--- a/third_party/WebKit/Source/core/frame/DOMTimer.h
+++ b/third_party/WebKit/Source/core/frame/DOMTimer.h
@@ -52,6 +52,10 @@
     // ActiveDOMObject
     void stop() override;
 
+    // The following are essentially constants. All intervals are in seconds.
+    static double hiddenPageAlignmentInterval();
+    static double visiblePageAlignmentInterval();
+
     // Eager finalization is needed to promptly stop this Timer object.
     // Otherwise timer events might fire at an object that's slated for destruction
     // (when lazily swept), but some of its members (m_action) may already have
@@ -72,6 +76,9 @@
     DOMTimer(ExecutionContext*, PassOwnPtrWillBeRawPtr<ScheduledAction>, int interval, bool singleShot, int timeoutID);
     void fired() override;
 
+    // Retuns timer fire time rounded to the next multiple of timer alignment interval.
+    double alignedFireTime(double) const override;
+
     WebTaskRunner* timerTaskRunner() override;
 
     int m_timeoutID;