detect preferences errors

chrome/browser/extensions/extensions_service.cc

 // Copyright (c) 2010 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/extensions_service.h"
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/histogram.h"
@@ skipping 403 matching lines @@
           backend_.get(),
           &ExtensionsServiceBackend::LoadSingleExtension,
           extension_path, scoped_refptr<ExtensionsService>(this)));
 }
 
 void ExtensionsService::LoadComponentExtensions() {
   for (RegisteredComponentExtensions::iterator it =
            component_extension_manifests_.begin();
        it != component_extension_manifests_.end(); ++it) {
     JSONStringValueSerializer serializer(it->manifest);
-    scoped_ptr<Value> manifest(serializer.Deserialize(NULL));
+    scoped_ptr<Value> manifest(serializer.Deserialize(NULL, NULL));
     if (!manifest.get()) {
       NOTREACHED() << "Failed to retrieve manifest for extension";
       continue;
     }
 
     scoped_ptr<Extension> extension(new Extension(it->root_directory));
     extension->set_location(Extension::COMPONENT);
 
     std::string error;
     if (!extension->InitFromValue(
@@ skipping 315 matching lines @@
   // EXTENSION_UNLOADED since that implies that the extension has been disabled
   // or uninstalled, and UnloadAll is just part of shutdown.
 }
 
 void ExtensionsService::ReloadExtensions() {
   UnloadAllExtensions();
   LoadAllExtensions();
 }
 
 void ExtensionsService::GarbageCollectExtensions() {
+  if (extension_prefs_->pref_service()->read_only())
+    return;
+
   InstalledExtensionSet installed(extension_prefs_.get());
   ChromeThread::PostTask(
       ChromeThread::FILE, FROM_HERE,
       NewRunnableFunction(
           &extension_file_util::GarbageCollectExtensions, install_directory_,
           installed.extensions(), installed.versions()));
 }
 
 void ExtensionsService::OnLoadedInstalledExtensions() {
   ready_ = true;
@@ skipping 475 matching lines @@
   // Finish installing on UI thread.
   ChromeThread::PostTask(
       ChromeThread::UI, FROM_HERE,
       NewRunnableMethod(
           frontend_,
           &ExtensionsService::ContinueLoadAllExtensions,
           extensions_to_reload,
           start_time,
           true));
 }