Add DCHECKs to StatefulExternalExtensionProvider

chrome/browser/extensions/external_policy_extension_provider.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/external_policy_extension_provider.h"
 
 #include "base/logging.h"
 #include "base/values.h"
 #include "chrome/common/pref_names.h"
+#include "chrome/browser/browser_thread.h"
 #include "chrome/browser/extensions/stateful_external_extension_provider.h"
 #include "chrome/browser/prefs/pref_service.h"
 
 namespace {
 
 // Check an extension ID and an URL to be syntactically correct.
 bool CheckExtension(std::string id, std::string update_url) {
   GURL url(update_url);
   if (!url.is_valid()) {
     LOG(WARNING) << "Policy specifies invalid update URL for external "
                  << "extension: " << update_url;
     return false;
   }
   if (!Extension::IdIsValid(id)) {
     LOG(WARNING) << "Policy specifies invalid ID for external "
                  << "extension: " << id;
     return false;
   }
   return true;
 }
 
 }
 
-ExternalPolicyExtensionProvider::ExternalPolicyExtensionProvider()
-  : StatefulExternalExtensionProvider(Extension::INVALID,
-                                      Extension::EXTERNAL_POLICY_DOWNLOAD) {
+ExternalPolicyExtensionProvider::ExternalPolicyExtensionProvider(
+    const ListValue* forcelist)
+        : StatefulExternalExtensionProvider(
+            Extension::INVALID,
+            Extension::EXTERNAL_POLICY_DOWNLOAD) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  ProcessPreferences(forcelist);
 }
 
 ExternalPolicyExtensionProvider::~ExternalPolicyExtensionProvider() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
 
 void ExternalPolicyExtensionProvider::SetPreferences(
     const ListValue* forcelist) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  ProcessPreferences(forcelist);
+}
+
+void ExternalPolicyExtensionProvider::ProcessPreferences(
+    const ListValue* forcelist) {
   DictionaryValue* result = new DictionaryValue();
   if (forcelist != NULL) {
     std::string extension_desc;
     for (ListValue::const_iterator it = forcelist->begin();
          it != forcelist->end(); ++it) {
       if (!(*it)->GetAsString(&extension_desc)) {
         LOG(WARNING) << "Failed to read forcelist string.";
       } else {
         // Each string item of the list has the following form:
         // extension_id_code;extension_update_url
         // The update URL might also contain semicolons.
         size_t pos = extension_desc.find(';');
         std::string id = extension_desc.substr(0, pos);
         std::string update_url = extension_desc.substr(pos+1);
         if (CheckExtension(id, update_url)) {
           result->SetString(id + ".external_update_url", update_url);
         }
       }
     }
   }
-  prefs_.reset(result);
+  set_prefs(result);
 }