Bug 1320704 - Disable IntersectionObserver, r=bkelly

dom/base/test/mochitest.ini

@@ -673,6 +673,7 @@ skip-if = (toolkit == 'android') # Android: Bug 775227
 [test_innersize_scrollport.html]
 [test_integer_attr_with_leading_zero.html]
 [test_intersectionobservers.html]
+skip-if = true # Track Bug 1320704
 [test_ipc_messagemanager_blob.html]
 [test_link_prefetch.html]
 skip-if = !e10s # Track Bug 1281415

dom/tests/mochitest/general/test_interfaces.html

@@ -615,9 +615,9 @@ var interfaceNamesInGlobalScope =
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "InstallTrigger",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "IntersectionObserver",
+    {name: "IntersectionObserver", disabled: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "IntersectionObserverEntry",
+    {name: "IntersectionObserverEntry", disabled: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "KeyEvent",
 // IMPORTANT: Do not change this list without review from a DOM peer!

dom/webidl/IntersectionObserver.webidl

@@ -7,7 +7,7 @@
  * https://wicg.github.io/IntersectionObserver/
  */
 
-[ProbablyShortLivingObject]
+[ProbablyShortLivingObject, Pref="dom.IntersectionObserver.enabled"]
 interface IntersectionObserverEntry {
   [Constant]
   readonly attribute DOMHighResTimeStamp time;
@@ -24,7 +24,8 @@ interface IntersectionObserverEntry {
 };
 
 [Constructor(IntersectionCallback intersectionCallback,
-             optional IntersectionObserverInit options)]
+             optional IntersectionObserverInit options),
+ Pref="dom.IntersectionObserver.enabled"]
 interface IntersectionObserver {
   [Constant]
   readonly attribute Element? root;