Remove navigator.vibrate without user gesture.

chrome/browser/flag_descriptions.cc

Index: chrome/browser/flag_descriptions.cc
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 18af4b8115408bb009a748367b64b1391ec4ca09..38166d67f412aefca2533458a4e50dd4a9b37f6f 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -2513,6 +2513,13 @@ const char kFramebustingDescription[] =
     "unless they are same-origin or the iframe is processing a user "
     "gesture.";
 
+const char kVibrateRequiresUserGestureName[] =
+    "Requiring user gesture for the Vibration API";
+
+const char kVibrateRequiresUserGestureDescription[] =
+    "Block the Vibration API if no user gesture has been received on "
+    "the frame or any embedded frame.";
+
 #if defined(OS_ANDROID)
 
 const char kEnableVrShellName[] = "Enable Chrome VR.";