[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 20addb9bae5c1675a0aaba4599bb3b765e1709e5..01b2090012bae19e2764ae6b10b58bfc1c660acd 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -232,6 +232,10 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (base::FeatureList::IsEnabled(features::kNewMediaPlaybackUi))
     WebRuntimeFeatures::enableNewMediaPlaybackUi(true);
 
+  if (base::FeatureList::IsEnabled(features::kBlockDocWriteIfEffectively2G)) {
+    WebRuntimeFeatures::enableBlockDocWriteIfEffectively2G(true);
+  }
+
   if (base::FeatureList::IsEnabled(features::kDocumentWriteEvaluator))
     WebRuntimeFeatures::enableDocumentWriteEvaluator(true);