[DocWriteBlocking] Add feature to block doc.written scripts if 2g-like network

content/child/runtime_features.cc

Index: content/child/runtime_features.cc
diff --git a/content/child/runtime_features.cc b/content/child/runtime_features.cc
index 2de3be63593a794fc4bb18bc7830f8a920e39b6c..6f9c0d43c4059c64f0840aa218d048014e2e2a3d 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -240,6 +240,10 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
     WebRuntimeFeatures::enableReloadwithoutSubResourceCacheRevalidation(true);
   }
 
+  if (base::FeatureList::IsEnabled(features::kBlockDocWriteIfEffectively2G)) {
+    WebRuntimeFeatures::enableBlockDocWriteIfEffectively2G(true);
+  }
+
   if (base::FeatureList::IsEnabled(features::kDocumentWriteEvaluator))
     WebRuntimeFeatures::enableDocumentWriteEvaluator(true);