Implement requestIdleCallback API

Source/core/dom/IdleRequestCallback.idl

Index: Source/core/dom/IdleRequestCallback.idl
diff --git a/Source/core/input/InputDeviceCapabilitiesInit.idl b/Source/core/dom/IdleRequestCallback.idl
similarity index 52%
copy from Source/core/input/InputDeviceCapabilitiesInit.idl
copy to Source/core/dom/IdleRequestCallback.idl
index e7ae86debbf39f39be3b5ece4134d3d4289be0a2..4fcaa8e043d7b13991fa6f06e63e37c47581068c 100644
--- a/Source/core/input/InputDeviceCapabilitiesInit.idl
+++ b/Source/core/dom/IdleRequestCallback.idl
@@ -3,7 +3,8 @@
 // found in the LICENSE file.
 
 [
-    RuntimeEnabled=InputDeviceCapabilities,
-] dictionary InputDeviceCapabilitiesInit {
-    boolean firesTouchEvents = false;
+  GarbageCollected,
+  RuntimeEnabled=RequestIdleCallback,
+] callback interface IdleRequestCallback {
+    void handleEvent(IdleCallbackDeadline deadline);
 };