Add a function for determining if official Google Chrome API key is used.

google_apis/google_api_keys.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 GOOGLE_APIS_GOOGLE_API_KEYS_H_
 #define GOOGLE_APIS_GOOGLE_API_KEYS_H_
 
 // If you add more includes to this file, you also need to add them to
 // google_api_keys_unittest.cc.
 #include <string>
@@ skipping 72 matching lines @@
 // e.g. URL-escaped if you use it in a URL.
 std::string GetOAuth2ClientID(OAuth2Client client);
 
 // Retrieves the OAuth2 client secret for the specified client, or the
 // empty string if not set.
 //
 // Note that the secret should be escaped for the context you use it
 // in, e.g. URL-escaped if you use it in a URL.
 std::string GetOAuth2ClientSecret(OAuth2Client client);
 
+// Returns if the API key using in the current build is the one for official
+// Google Chrome.
+bool IsGoogleChromeAPIKeyUsed();
+
 }  // namespace google_apis
 
 #endif  // GOOGLE_APIS_GOOGLE_API_KEYS_H_