Content Settings: Add RevocationObserver to measure when permissions are revoked

chrome/browser/permissions/permission_util.h

 // Copyright 2015 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_UTIL_H_
 #define CHROME_BROWSER_PERMISSIONS_PERMISSION_UTIL_H_
 
 #include <string>
 
 #include "base/macros.h"
+#include "components/content_settings/core/common/content_settings.h"
 #include "components/content_settings/core/common/content_settings_types.h"
 
+class GURL;
+class Profile;
+
 namespace content {
 enum class PermissionType;
 }  // namespace content
 
 // A utility class for permissions.
 class PermissionUtil {
  public:
   // Returns the permission string for the given PermissionType.
   static std::string GetPermissionString(content::PermissionType permission);
 
   // Limited conversion of ContentSettingsType to PermissionType. Intended for
   // recording Permission UMA metrics from areas of the codebase which have not
   // yet been converted to PermissionType. Returns true if the conversion was
   // performed.
   // TODO(tsergeant): Remove this function once callsites operate on
   // PermissionType directly.
   static bool GetPermissionType(ContentSettingsType type,
                                 content::PermissionType* out);
 
+  // Helper method which proxies
+  // HostContentSettingsMap::SetContentSettingDefaultScope(). Checks the content
+  // setting value before and after the change to determine whether it has gone
+  // from ALLOW to BLOCK or ASK, and records metrics accordingly. Should be
+  // called from UI code when a user changes permissions for a particular origin
+  // pair.
+  // TODO(tsergeant): This is a temporary solution to begin gathering metrics.
+  // We should integrate this better with the permissions layer. See
+  // crbug.com/469221.
+  static void SetContentSettingAndRecordRevocation(
+      Profile* profile,
+      const GURL& primary_url,
+      const GURL& secondary_url,
+      ContentSettingsType content_type,
+      std::string resource_identifier,
+      ContentSetting setting);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PermissionUtil);
 };
 
 #endif  // CHROME_BROWSER_PERMISSIONS_PERMISSION_UTIL_H_