Perform install tasks for newly installed or upgraded component apps/extensions.

chrome/browser/extensions/extension_prefs.cc

 // 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.
 
 #include "chrome/browser/extensions/extension_prefs.h"
 
 #include "base/command_line.h"
 #include "base/prefs/pref_notifier.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
@@ skipping 1635 matching lines @@
 scoped_ptr<ExtensionInfo> ExtensionPrefs::GetInstalledExtensionInfo(
     const std::string& extension_id) const {
   const DictionaryValue* ext;
   const DictionaryValue* extensions = prefs_->GetDictionary(kExtensionsPref);
   if (!extensions ||
       !extensions->GetDictionaryWithoutPathExpansion(extension_id, &ext))
     return scoped_ptr<ExtensionInfo>();
   if (IsBlacklistBitSet(ext))
     return scoped_ptr<ExtensionInfo>();
   int state_value;
-  if (!ext->GetInteger(kPrefState, &state_value)) {
-    // This can legitimately happen if we store preferences for component
-    // extensions.
+  if (!ext->GetInteger(kPrefState, &state_value) ||
+      state_value == Extension::ENABLED_COMPONENT) {
+    // Old preferences files may not have kPrefState for component extensions.
     return scoped_ptr<ExtensionInfo>();
   }
+
   if (state_value == Extension::EXTERNAL_EXTENSION_UNINSTALLED) {
     LOG(WARNING) << "External extension with id " << extension_id
                  << " has been uninstalled by the user";
     return scoped_ptr<ExtensionInfo>();
   }
   FilePath::StringType path;
   int location_value;
   if (!ext->GetInteger(kPrefLocation, &location_value))
     return scoped_ptr<ExtensionInfo>();
 
@@ skipping 642 matching lines @@
     const ExtensionIdList& strings) {
   ListPrefUpdate update(prefs_, pref);
   ListValue* list_of_values = update.Get();
   list_of_values->Clear();
   for (ExtensionIdList::const_iterator iter = strings.begin();
        iter != strings.end(); ++iter)
     list_of_values->Append(new StringValue(*iter));
 }
 
 }  // namespace extensions