Content Settings: Add RevocationObserver to measure when permissions are revoked

chrome/browser/permissions/permission_uma_util.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PERMISSIONS_PERMISSION_UMA_UTIL_H_
 #define CHROME_BROWSER_PERMISSIONS_PERMISSION_UMA_UTIL_H_
 
 #include "base/logging.h"
 #include "base/macros.h"
 
 class GURL;
 class Profile;
 
 namespace content {
 enum class PermissionType;
 }  // namespace content
 
+// Enum for UMA purposes, make sure you update histograms.xml if you add new
+// permission actions. Never delete or reorder an entry; only add new entries
+// immediately before PERMISSION_NUM
+enum PermissionAction {
+  GRANTED = 0,
+  DENIED = 1,
+  DISMISSED = 2,
+  IGNORED = 3,
+  REVOKED = 4,
+  REENABLED = 5,
+  REQUESTED = 6,
+
+  // Always keep this at the end.
+  PERMISSION_ACTION_NUM,
+};
+
 // Provides a convenient way of logging UMA for permission related operations.
 class PermissionUmaUtil {
  public:
   static void PermissionRequested(content::PermissionType permission,
                                   const GURL& requesting_origin,
                                   const GURL& embedding_origin,
                                   Profile* profile);
   static void PermissionGranted(content::PermissionType permission,
                                 const GURL& requesting_origin);
   static void PermissionDenied(content::PermissionType permission,
                                const GURL& requesting_origin);
   static void PermissionDismissed(content::PermissionType permission,
                                   const GURL& requesting_origin);
   static void PermissionIgnored(content::PermissionType permission,
                                 const GURL& requesting_origin);
   static void PermissionRevoked(content::PermissionType permission,
                                 const GURL& revoked_origin);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PermissionUmaUtil);
 };
 
 #endif  // CHROME_BROWSER_PERMISSIONS_PERMISSION_UMA_UTIL_H_