Enable the new bookmarks UI feature flag by default on iOS.

Bug: 782127
Change-Id: Id683ed53061f2a34a73e5af96cb307c9b73d3069
Reviewed-on: https://chromium-review.googlesource.com/768509Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Marti Wong <martiw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516270}

ios/chrome/browser/bookmarks/bookmark_new_generation_features.cc

@@ -6,4 +6,4 @@
 
 // Feature flag for the new bookmark UI
 const base::Feature kBookmarkNewGeneration{"BookmarkNewGeneration",
-                                           base::FEATURE_DISABLED_BY_DEFAULT};
+                                           base::FEATURE_ENABLED_BY_DEFAULT};