Add concept of an options page to Extensions....

chrome/common/extensions/extension_constants.h

 // Copyright (c) 2009 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_EXTENSIONS_EXTENSION_CONSTANTS_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_
 
 // Keys used in JSON representation of extensions.
 namespace extension_manifest_keys {
   extern const wchar_t* kBackground;
@@ skipping 29 matching lines @@
   extern const wchar_t* kThemeColors;
   extern const wchar_t* kThemeTints;
   extern const wchar_t* kThemeDisplayProperties;
   extern const wchar_t* kToolstripMoleHeight;
   extern const wchar_t* kToolstripMolePath;
   extern const wchar_t* kToolstripPath;
   extern const wchar_t* kToolstrips;
   extern const wchar_t* kType;
   extern const wchar_t* kVersion;
   extern const wchar_t* kUpdateURL;
+  extern const wchar_t* kOptionsPage;
 }  // namespace extension_manifest_keys
 
 // Some values expected in manifests.
 namespace extension_manifest_values {
   extern const char* kRunAtDocumentStart;
   extern const char* kRunAtDocumentEnd;
   extern const char* kPageActionTypeTab;
   extern const char* kPageActionTypePermanent;
 }  // namespace extension_manifest_values
 
@@ skipping 49 matching lines @@
   extern const char* kInvalidThemeTints;
   extern const char* kOneUISurfaceOnly;
   extern const char* kThemesCannotContainExtensions;
   extern const char* kManifestParseError;
   extern const char* kManifestUnreadable;
   extern const char* kMissingFile;
   extern const char* kInvalidUpdateURL;
   extern const char* kInvalidDefaultLocale;
   extern const char* kLocalesNoDefaultLocaleSpecified;
   extern const char* kLocalesNoValidLocaleNamesListed;
+  extern const char* kInvalidOptionsPage;
 }  // namespace extension_manifest_errors
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_