Add enable flag for pointer events in about://flags

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 ba2787d96d91e0248b5fd75408d73e7b62415625..44eaf6d99d882227574d6f041c16e8b1b474e07c 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -198,6 +198,11 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   WebRuntimeFeatures::enableMediaDocumentDownloadButton(
       base::FeatureList::IsEnabled(features::kMediaDocumentDownloadButton));
 
+  if (base::FeatureList::IsEnabled(features::kPointerEvents)) {
+      WebRuntimeFeatures::enableFeatureFromString(
+        std::string("PointerEvent"), true);
+  }
+
   // Enable explicitly enabled features, and then disable explicitly disabled
   // ones.
   if (command_line.HasSwitch(switches::kEnableBlinkFeatures)) {