Sync IntersectionObserver IDL with the spec

third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl

Index: third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl b/third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl
index 3a6956c2867395178ae1bbd6821fccaf312510b2..5cfe2843268aeade4706dfebfaf13a2f39f561a9 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl
@@ -2,15 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// https://github.com/slightlyoff/IntersectionObserver
+// https://wicg.github.io/IntersectionObserver/#intersection-observer-entry
 
 [
     RuntimeEnabled=IntersectionObserver,
 ] interface IntersectionObserverEntry {
+    readonly attribute DOMHighResTimeStamp time;
+    // TODO(szager): |rootBounds| should not be nullable and it,
+    // |boundingClientRect| and |intersectionRect| should all be
+    // DOMRectReadOnly.
+    readonly attribute ClientRect? rootBounds;
     readonly attribute ClientRect boundingClientRect;
     readonly attribute ClientRect intersectionRect;
     readonly attribute double intersectionRatio;
-    readonly attribute ClientRect? rootBounds;
     readonly attribute Element target;
-    readonly attribute DOMHighResTimeStamp time;
 };