Revert of Move throttling of background timers into the renderer scheduler

third_party/WebKit/Source/core/page/Page.cpp

Index: third_party/WebKit/Source/core/page/Page.cpp
diff --git a/third_party/WebKit/Source/core/page/Page.cpp b/third_party/WebKit/Source/core/page/Page.cpp
index 3ec85f1254f91bb4ac9abccee16d1df793bf00e3..dac637d20e4d5dcfc021aebc504f1456fbc2820e 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -117,6 +117,7 @@
     , m_tabKeyCyclesThroughElements(true)
     , m_defersLoading(false)
     , m_deviceScaleFactor(1)
+    , m_timerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval())
     , m_visibilityState(PageVisibilityStateVisible)
     , m_isCursorVisible(true)
 #if ENABLE(ASSERT)
@@ -355,15 +356,41 @@
     }
 }
 
+void Page::setTimerAlignmentInterval(double interval)
+{
+    if (interval == m_timerAlignmentInterval)
+        return;
+
+    m_timerAlignmentInterval = interval;
+    for (Frame* frame = mainFrame(); frame; frame = frame->tree().traverseNextWithWrap(false)) {
+        if (!frame->isLocalFrame())
+            continue;
+
+        if (Document* document = toLocalFrame(frame)->document()) {
+            if (DOMTimerCoordinator* timers = document->timers()) {
+                timers->didChangeTimerAlignmentInterval();
+            }
+        }
+    }
+}
+
+double Page::timerAlignmentInterval() const
+{
+    return m_timerAlignmentInterval;
+}
+
 void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitialState)
 {
     if (m_visibilityState == visibilityState)
         return;
     m_visibilityState = visibilityState;
 
+    // TODO(alexclarke): Move throttling of timers to chromium.
     if (visibilityState == PageVisibilityStateVisible) {
+        setTimerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval());
         memoryPurgeController().pageBecameActive();
     } else {
+        setTimerAlignmentInterval(DOMTimer::hiddenPageAlignmentInterval());
         if (!isInitialState)
             memoryPurgeController().pageBecameInactive();
     }