Reland: Implement Aura side of unified touch text selection for contents

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 b13ccc219aba59e003e9710e87e0da18bc2fc291..ca7be4c53c2e0349f42f20169a6af5f86c8cea6b 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -56,7 +56,6 @@ static void SetRuntimeFeatureDefaultsForPlatform() {
   WebRuntimeFeatures::enableOrientationEvent(true);
   WebRuntimeFeatures::enableFastMobileScrolling(true);
   WebRuntimeFeatures::enableMediaCapture(true);
-  WebRuntimeFeatures::enableCompositedSelectionUpdate(true);
   // If navigation transitions gets activated via field trial, enable it in
   // blink. We don't set this to false in case the user has manually enabled
   // the feature via experimental web platform features.
@@ -69,6 +68,10 @@ static void SetRuntimeFeatureDefaultsForPlatform() {
   WebRuntimeFeatures::enableNavigatorContentUtils(true);
 #endif  // defined(OS_ANDROID)
 
+#if defined(OS_ANDROID) || defined(USE_AURA)
+  WebRuntimeFeatures::enableCompositedSelectionUpdate(true);
+#endif
+
 #if !(defined OS_ANDROID || defined OS_CHROMEOS || defined OS_IOS)
     // Only Android, ChromeOS, and IOS support NetInfo right now.
     WebRuntimeFeatures::enableNetworkInformation(false);