Remove RequestIdleCallback runtime flag (status=stable)

third_party/WebKit/Source/core/frame/Window.idl

Index: third_party/WebKit/Source/core/frame/Window.idl
diff --git a/third_party/WebKit/Source/core/frame/Window.idl b/third_party/WebKit/Source/core/frame/Window.idl
index fb6de0a9bd4f0e3a0695a596462a11e9b742af3d..0dfdb5338f70f667c4f533b3303fe6f6a068a08b 100644
--- a/third_party/WebKit/Source/core/frame/Window.idl
+++ b/third_party/WebKit/Source/core/frame/Window.idl
@@ -81,8 +81,8 @@
     [MeasureAs=UnprefixedRequestAnimationFrame] long requestAnimationFrame(FrameRequestCallback callback);
     void cancelAnimationFrame(long handle);
 
-    [Measure, RuntimeEnabled=RequestIdleCallback] long requestIdleCallback(IdleRequestCallback callback, optional IdleRequestOptions options);
-    [RuntimeEnabled=RequestIdleCallback] void cancelIdleCallback(long handle);
+    [Measure] long requestIdleCallback(IdleRequestCallback callback, optional IdleRequestOptions options);
+    void cancelIdleCallback(long handle);
 
     [DoNotCheckSecurity, Custom, RaisesException] void postMessage(any message, DOMString targetOrigin, optional sequence<Transferable> transfer);