import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 1257418 - Remove USE_DEPENDENT_LIBS. r=gps (fbe746751a)
- Bug 1255817 part 3. Remove the now-unreachable JS_ReportPendingException call in nsXPCWrappedJSClass::CallQueryInterfaceOnJSObject. r=bholley (dbffe901a9)
- Bug 1255817 part 4. Make XPCJSRuntime use MozCrashErrorReporter by default, now that there should be no stray JS_ReportPendingException calls. r=bholley (68d82e4b68)
- Bug 1245000 part 1 - Add a preference for enabling Element.animate; r=bz (d94ab6f1d9)
- Bug 1245000 part 2 - Don't ship Animation.ready; r=bz (129a052a16)
- Bug 1245000 part 3 - Turn on Element.animate in release channels too; r=bz (cc6743c31d)
- Bug 1245000 part 4 - Enable the Animation constructor when Element.animate is enabled; r=bz (8a65bdedcb)
- Bug 1247685 - WebIDL and DOM implementation changes for app server keys. r=mt,baku (69870bd979)
- Bug 1248565 - Introduce MOZ_LOG_* variables for mozilla logging. r=erahm (ea236d3b26)
- Bug 1258231 - Lock while iterating console messages. r=mccr8 (2b54be114d)
- bug 1252104 - make NS_ERROR_GET_CODE() and NS_ERROR_GET_MODULE() constexpr r=froydnj (f29ae0f6de)
- Bug 1221160 - fix AutoTraceLogLock deadlock on Windows; r=froydnj (11f1c2a071)
- Bug 1251895 - don't race on nsTraceRefcnt's object serial number tables; r=mccr8 (2d52aceffe)

dom/base/nsDocument.cpp

@@ -3198,6 +3198,16 @@ nsDocument::GetUndoManager()
   return undoManager.forget();
 }
 
+bool
+nsDocument::IsElementAnimateEnabled(JSContext* /*unused*/, JSObject* /*unused*/)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  return nsContentUtils::IsCallerChrome() ||
+         Preferences::GetBool("dom.animations-api.core.enabled") ||
+         Preferences::GetBool("dom.animations-api.element-animate.enabled");
+}
+
 bool
 nsDocument::IsWebAnimationsEnabled(JSContext* /*unused*/, JSObject* /*unused*/)
 {