Implement requestIdleCallback API

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index ee489891be8a61edfec1ee620e8b022306080c69..487ba69a9883c1165fc6696e38a2e4e24c0376e3 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -119,6 +119,7 @@ class HTMLImportsController;
 class HTMLLinkElement;
 class HTMLScriptElement;
 class HitTestRequest;
+class IdleRequestCallback;
 class LayoutPoint;
 class LiveNodeListBase;
 class Locale;
@@ -142,6 +143,7 @@ class SVGUseElement;
 class ScriptRunner;
 class ScriptableDocumentParser;
 class ScriptedAnimationController;
+class ScriptedIdleTaskController;
 class SecurityOrigin;
 class SegmentedString;
 class SelectorQueryCache;
@@ -956,6 +958,9 @@ public:
     void cancelAnimationFrame(int id);
     void serviceScriptedAnimations(double monotonicAnimationStartTime);
 
+    int requestIdleFrame(IdleRequestCallback*);
+    void cancelIdleFrame(int id);
+
     virtual EventTarget* errorEventTarget() override final;
     virtual void logExceptionToConsole(const String& errorMessage, int scriptId, const String& sourceURL, int lineNumber, int columnNumber, PassRefPtrWillBeRawPtr<ScriptCallStack>) override final;
 
@@ -1092,6 +1097,7 @@ private:
     bool isElementNode() const = delete; // This will catch anyone doing an unnecessary check.
 
     ScriptedAnimationController& ensureScriptedAnimationController();
+    ScriptedIdleTaskController& ensureScriptedIdleTaskController();
     virtual SecurityContext& securityContext() override final { return *this; }
     virtual EventQueue* eventQueue() const override final;
 
@@ -1371,6 +1377,7 @@ private:
     unsigned m_writeRecursionDepth;
 
     RefPtrWillBeMember<ScriptedAnimationController> m_scriptedAnimationController;
+    RefPtrWillBeMember<ScriptedIdleTaskController> m_scriptedIdleTaskController;
     OwnPtr<MainThreadTaskRunner> m_taskRunner;
     OwnPtrWillBeMember<TextAutosizer> m_textAutosizer;