Revert "FORK: Disable WebAnimationsCSS"

Bug: 12393371

This reverts commit d27dc098443975487354b187165a69ee95b04be4.
The proper fix for this change
 http://src.chromium.org/viewvc/blink?view=rev&rev=165030
is now pushed to internal M33 tree.

Change-Id: Ia9d47a72cb3f7c1bd0f453a9cc3f4f998826792b
diff --git a/Source/platform/RuntimeEnabledFeatures.in b/Source/platform/RuntimeEnabledFeatures.in
index 72a2261..91674bb 100644
--- a/Source/platform/RuntimeEnabledFeatures.in
+++ b/Source/platform/RuntimeEnabledFeatures.in
@@ -123,7 +123,7 @@
 UserSelectAll status=experimental
 Vibration status=stable
 VideoTrack depends_on=Media, status=stable
-WebAnimationsCSS status=experimental
+WebAnimationsCSS status=stable
 WebAnimationsSVG depends_on=WebAnimationsCSS
 WebAnimationsAPI depends_on=WebAnimationsCSS, status=experimental
 WebAudio condition=WEB_AUDIO, status=stable