Remove navigator.vibrate without user gesture.

content/public/common/content_features.cc

Index: content/public/common/content_features.cc
diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
index 4a1d40e83a760fc089824a470558320758b2f50e..5f0250a324822355086b4926d4e4d7e953ce97d5 100644
--- a/content/public/common/content_features.cc
+++ b/content/public/common/content_features.cc
@@ -235,6 +235,10 @@ const base::Feature kTokenBinding{"token-binding",
 const base::Feature kTouchpadAndWheelScrollLatching{
     "TouchpadAndWheelScrollLatching", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Controls whether vibrate requires user gesture.
+const base::Feature kVibrateRequiresUserGesture{
+    "VibrateRequiresUserGesture", base::FEATURE_ENABLED_BY_DEFAULT};
+
 // Enables VR UI.
 const base::Feature kVrShell{"VrShell", base::FEATURE_DISABLED_BY_DEFAULT};