Enable SkTextBlob caching

Makes recording flights-app 15% faster.

R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/859353002

sky/engine/platform/RuntimeEnabledFeatures.in

diff --git a/sky/engine/platform/RuntimeEnabledFeatures.in b/sky/engine/platform/RuntimeEnabledFeatures.in
index 18c021b..f5b0af5 100644
--- a/sky/engine/platform/RuntimeEnabledFeatures.in
+++ b/sky/engine/platform/RuntimeEnabledFeatures.in
@@ -117,7 +117,7 @@
 // Temporary setting to allow easy rollback of change to hover media feature.
 HoverMediaQueryKeywords status=stable
 
-TextBlob
+TextBlob status=stable
 TouchIconLoading
 UserSelectAll status=experimental
 WebGLDraftExtensions status=experimental