Apply automatic range checks to /chrome enum types across IPC.

chrome/common/search_provider.h

 // Copyright (c) 2012 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_COMMON_SEARCH_PROVIDER_H_
 #define CHROME_COMMON_SEARCH_PROVIDER_H_
 
 namespace search_provider {
 
 // The type of OSDD that the renderer is giving to the browser.
 enum OSDDType {
   // The Open Search Description URL was detected automatically.
   AUTODETECTED_PROVIDER,
 
   // The Open Search Description URL was given by Javascript.
   EXPLICIT_PROVIDER,
+  OSDD_TYPE_LAST = EXPLICIT_PROVIDER
 };
 
 // The install state of the search provider (not installed, installed, default).
 enum InstallState {
   // Equates to an access denied error.
   DENIED = -1,
 
   // DON'T CHANGE THE VALUES BELOW.
   // All of the following values are manidated by the
   // spec for window.external.IsSearchProviderInstalled.
 
   // The search provider is not installed.
   NOT_INSTALLED = 0,
 
   // The search provider is in the user's set but is not
   INSTALLED_BUT_NOT_DEFAULT = 1,
 
   // The search provider is set as the user's default.
   INSTALLED_AS_DEFAULT = 2
 };
 
 }  // namespace search_provider
 
 #endif  // CHROME_COMMON_SEARCH_PROVIDER_H_