Add a method to classify what permission class an extension is in, with unit

chrome/common/extensions/extension.cc

 // 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.
 
 #include "chrome/common/extensions/extension.h"
 
 #include "app/resource_bundle.h"
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ skipping 935 matching lines @@
     const std::vector<std::string>& icon_paths = it->second->icon_paths();
     for (std::vector<std::string>::const_iterator iter = icon_paths.begin();
          iter != icon_paths.end(); ++iter) {
       image_paths.insert(FilePath::FromWStringHack(UTF8ToWide(*iter)));
     }
   }
 
   return image_paths;
 }
 
+Extension::PermissionClass Extension::GetPermissionClass() {
+  // Native code can do anything. Highest class.
+  if (!plugins_.empty())
+    return PERMISSION_CLASS_FULL;
+
+  // Access to other sites means the extension can steal cookies (login data)
+  // from those sites.
+  // TODO(mpcomplete): should we only classify for host access outside the
+  // extension's origin? how?
+  if (!host_permissions_.empty() || !content_scripts_.empty())
+    return PERMISSION_CLASS_HIGH;
+
+  // Extension can access history data, bookmarks, other personal info.
+  if (!api_permissions_.empty())
+    return PERMISSION_CLASS_MEDIUM;
+
+  return PERMISSION_CLASS_LOW;
+}
+
 bool Extension::GetBackgroundPageReady() {
   return background_page_ready_ || background_url().is_empty();
 }
 
 void Extension::SetBackgroundPageReady() {
   DCHECK(!background_url().is_empty());
   background_page_ready_ = true;
   NotificationService::current()->Notify(
       NotificationType::EXTENSION_BACKGROUND_PAGE_READY,
       Source<Extension>(this),
       NotificationService::NoDetails());
 }