Add minimum version to extension management

chrome/browser/extensions/extension_management_constants.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_EXTENSIONS_EXTENSION_MANAGEMENT_CONSTANTS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_CONSTANTS_H_
 
 #include <string>
 
 #include "extensions/common/manifest.h"
 
 namespace extensions {
 namespace schema_constants {
 
 extern const char kWildcard[];
 
 extern const char kInstallationMode[];
 extern const char kAllowed[];
 extern const char kBlocked[];
 extern const char kForceInstalled[];
 extern const char kNormalInstalled[];
 
 extern const char kBlockedPermissions[];
 extern const char kAllowedPermissions[];
 
 extern const char kUpdateUrl[];
 extern const char kInstallSources[];
 extern const char kAllowedTypes[];
 
+extern const char kMinimumVersion[];
+
 extern const char kUpdateUrlPrefix[];
 
 struct AllowedTypesMapEntry {
   // Name of allowed types of extensions used in schema of extension
   // management preference.
   const char* name;
   // The corresponding Manifest::Type.
   Manifest::Type manifest_type;
 };
 
 extern const size_t kAllowedTypesMapSize;
 extern const AllowedTypesMapEntry kAllowedTypesMap[];
 
 // Helper fuction over |kAllowedTypesMap|, returns Manifest::TYPE_UNKNOWN if
 // not found.
 Manifest::Type GetManifestType(const std::string& name);
 
 }  // namespace schema_constants
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_CONSTANTS_H_