Enable full testing of CSSReducedFontLoadingLayoutInvalidations

This is preparation for enabling finch experiments of the feature on M85

Note: though M85 hasn't reached Beta, we'd like to have it covered by
test bots first to catch any breakage. We'd also like it to be tested
by perf bots, since this "feature" is a performance optimization.

Bug: 441925
Change-Id: I3ef98ffcfa960381efd034cd1cd63e55fbda4b01
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231269
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775847}

content/child/runtime_features.cc

@@ -351,6 +351,9 @@ void SetRuntimeFeaturesFromChromiumFeatures() {
           {"CSSReducedFontLoadingInvalidations",
            blink::features::kCSSReducedFontLoadingInvalidations,
            kUseFeatureState},
+          {"CSSReducedFontLoadingLayoutInvalidations",
+           blink::features::kCSSReducedFontLoadingLayoutInvalidations,
+           kUseFeatureState},
           {"FeaturePolicyForClientHints",
            features::kFeaturePolicyForClientHints, kUseFeatureState},
           {"FlexGaps", blink::features::kFlexGaps, kEnableOnly},

testing/variations/fieldtrial_testing_config.json

@@ -1225,6 +1225,27 @@
             ]
         }
     ],
+    "CSSReducedFontLoadingLayoutInvalidations": [
+        {
+            "platforms": [
+                "android",
+                "android_weblayer",
+                "android_webview",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "CSSReducedFontLoadingLayoutInvalidations"
+                    ]
+                }
+            ]
+        }
+    ],
     "CacheStorageEagerReading": [
         {
             "platforms": [

third_party/blink/common/features.cc

@@ -461,6 +461,9 @@ const base::Feature kDawn2dCanvas{"Dawn2dCanvas",
 
 const base::Feature kCSSReducedFontLoadingInvalidations{
     "CSSReducedFontLoadingInvalidations", base::FEATURE_DISABLED_BY_DEFAULT};
+const base::Feature kCSSReducedFontLoadingLayoutInvalidations{
+    "CSSReducedFontLoadingLayoutInvalidations",
+    base::FEATURE_DISABLED_BY_DEFAULT};
 
 // When enabled, frees up CachedMetadata after consumption by script resources
 // and modules. Needed for the experiment in http://crbug.com/1045052.

third_party/blink/public/common/features.h

@@ -146,6 +146,8 @@ BLINK_COMMON_EXPORT extern const base::Feature kDawn2dCanvas;
 
 BLINK_COMMON_EXPORT extern const base::Feature
     kCSSReducedFontLoadingInvalidations;
+BLINK_COMMON_EXPORT extern const base::Feature
+    kCSSReducedFontLoadingLayoutInvalidations;
 
 BLINK_COMMON_EXPORT extern const base::Feature kDiscardCodeCacheAfterFirstUse;