Enforce the 'requirements' field in manifests.

chrome/browser/extensions/extension_prefs.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_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 129 matching lines @@
 
   // Did the extension ask to escalate its permission during an upgrade?
   bool DidExtensionEscalatePermissions(const std::string& id);
 
   // If |did_escalate| is true, the preferences for |extension| will be set to
   // require the install warning when the user tries to enable.
   void SetDidExtensionEscalatePermissions(
       const Extension* extension,
       bool did_escalate);
 
+  // Does the extension declare requirements that the system does not meet?
+  bool HasUnsupportedRequirements(const std::string& extension_id);
+
+  // Remove any unsupported requirement warnings that this extension has.
+  void ClearUnsupportedRequirements(const std::string& extension_id);
+
+  void SetUnsupportedRequirements(const std::string& extension_id,
+                                  std::vector<std::string> requirement_errors);
+
+  std::vector<std::string> GetUnsupportedRequirements(
+      const std::string& extension_id);
+
   // Getter and setters for disabled reason.
   Extension::DisableReason GetDisableReason(
       const std::string& extension_id);
   void SetDisableReason(const std::string& extension_id,
                         Extension::DisableReason disable_reason);
   void RemoveDisableReason(const std::string& extension_id);
 
   // Returns the version string for the currently installed extension, or
   // the empty string if not found.
   std::string GetVersionString(const std::string& extension_id);
@@ skipping 398 matching lines @@
   scoped_ptr<ExtensionSorting> extension_sorting_;
 
   scoped_refptr<ContentSettingsStore> content_settings_store_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_