Delete the omahaproxy-backed extension blacklist and clear its entries from the

chrome/browser/chromeos/extensions/external_cache.cc

 // Copyright (c) 2013 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/chromeos/extensions/external_cache.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/files/file_enumerator.h"
@@ skipping 145 matching lines @@
   // a reference to the arguments.
   PostBlockingTask(FROM_HERE,
                    base::Bind(&ExternalCache::BlockingInstallCacheEntry,
                               weak_ptr_factory_.GetWeakPtr(),
                               std::string(cache_dir_),
                               std::string(id),
                               base::FilePath(path),
                               std::string(version)));
 }
 
-void ExternalCache::OnBlacklistDownloadFinished(
-    const std::string& data,
-    const std::string& package_hash,
-    const std::string& version,
-    const extensions::ExtensionDownloaderDelegate::PingResult& ping_result,
-    const std::set<int>& request_ids) {
-  NOTREACHED();
-}
-
 bool ExternalCache::IsExtensionPending(const std::string& id) {
   // Pending means that there is no installed version yet.
   return extensions_->HasKey(id) && !cached_extensions_->HasKey(id);
 }
 
 bool ExternalCache::GetExtensionExistingVersion(const std::string& id,
                                                 std::string* version) {
   DictionaryValue* extension_dictionary = NULL;
   if (cached_extensions_->GetDictionary(id, &extension_dictionary)) {
     return extension_dictionary->GetString(
@@ skipping 306 matching lines @@
 
 void ExternalCache::PostBlockingTask(const tracked_objects::Location& location,
                                      const base::Closure& task) {
   content::BrowserThread::GetBlockingPool()->
       PostSequencedWorkerTaskWithShutdownBehavior(
           worker_pool_token_, location, task,
           base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 }
 
 }  // namespace chromeos