RubyNG: Enable the feature by default.

This CL adds base::Feature for LayoutNGRuby runtime flag.  We can
disable the feature by Finch when we find a critical bug of the feature.

Bug: 1069817
Change-Id: I93385fd2e6a67acad7af3e45310e254b6692f504
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2250140
Auto-Submit: Kent Tamura <tkent@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779663}

content/child/runtime_features.cc

@@ -377,6 +377,7 @@ void SetRuntimeFeaturesFromChromiumFeatures() {
           {"LayoutNGFlexBox", blink::features::kFlexNG, kUseFeatureState},
           {"LayoutNGFragmentItem", blink::features::kFragmentItem,
            kUseFeatureState},
+          {"LayoutNGRuby", blink::features::kLayoutNGRuby, kUseFeatureState},
           {"LegacyWindowsDWriteFontFallback",
            features::kLegacyWindowsDWriteFontFallback, kUseFeatureState},
           {"LinkDisabledNewSpecBehavior",

third_party/blink/common/features.cc

@@ -71,6 +71,10 @@ const base::Feature kTopLevelAwait{"TopLevelAwait",
 // Enable LayoutNG.
 const base::Feature kLayoutNG{"LayoutNG", base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Enable LayoutNGRuby by default. This feature is for a kill switch.
+const base::Feature kLayoutNGRuby{"LayoutNGRuby",
+                                  base::FEATURE_ENABLED_BY_DEFAULT};
+
 const base::Feature kFragmentItem{"FragmentItem",
                                   base::FEATURE_DISABLED_BY_DEFAULT};
 

third_party/blink/public/common/features.h

@@ -33,6 +33,7 @@ BLINK_COMMON_EXPORT extern const base::Feature kJSONModules;
 BLINK_COMMON_EXPORT extern const base::Feature kForceSynchronousHTMLParsing;
 BLINK_COMMON_EXPORT extern const base::Feature kTopLevelAwait;
 BLINK_COMMON_EXPORT extern const base::Feature kLayoutNG;
+BLINK_COMMON_EXPORT extern const base::Feature kLayoutNGRuby;
 BLINK_COMMON_EXPORT extern const base::Feature kFragmentItem;
 BLINK_COMMON_EXPORT extern const base::Feature kMixedContentAutoupgrade;
 BLINK_COMMON_EXPORT extern const base::Feature kNavigationPredictor;