IntersectionObserver: second cut.

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
new file mode 100644
index 0000000000000000000000000000000000000000..7e0045d7a628bc8dd76a93c34b9402f304d91068
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserverEntry.idl
@@ -0,0 +1,15 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// 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
+
+[
+    GarbageCollected,
+] interface IntersectionObserverEntry {
+    readonly attribute ClientRect boundingClientRect;

[esprehn, 2015/12/12 00:14:16]

properties are always stable in IDL unless they're written with [NewObject],
that means you need to cache the ClientRect objects as members

[szager1, 2015/12/16 19:15:37]

Done.

+    readonly attribute ClientRect intersectionRect;
+    readonly attribute ClientRect rootBounds;
+    readonly attribute Element target;
+    readonly attribute DOMHighResTimeStamp time;
+};