Tests: Simplify SequencedWorkerPoolOwner, call Shutdown on destructor.

chrome/browser/extensions/updater/local_extension_cache_unittest.cc

 // Copyright 2014 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/updater/local_extension_cache.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 30 matching lines @@
   }
 
   // testing::Test overrides:
   void SetUp() override {
     pool_owner_.reset(
         new base::SequencedWorkerPoolOwner(3, "Background Pool"));
     background_task_runner_ = pool_owner_->pool()->GetSequencedTaskRunner(
         pool_owner_->pool()->GetNamedSequenceToken("background"));
   }
 
-  void TearDown() override {
-    pool_owner_->pool()->Shutdown();
-    base::RunLoop().RunUntilIdle();
-  }
-
   base::FilePath CreateCacheDir(bool initialized) {
     EXPECT_TRUE(cache_dir_.CreateUniqueTempDir());
     if (initialized)
       CreateFlagFile(cache_dir_.path());
     return cache_dir_.path();
   }
 
   base::FilePath CreateTempDir() {
     EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
     return temp_dir_.path();
@@ skipping 415 matching lines @@
   const base::FilePath hashed2 =
       GetExtensionFileName(cache_dir, kTestExtensionId1, "3.0", hash4);
   EXPECT_TRUE(base::PathExists(hashed2));
   EXPECT_TRUE(cache.GetExtension(kTestExtensionId1, hash4, NULL, NULL));
   // Old file kept
   EXPECT_TRUE(cache.GetExtension(kTestExtensionId1, hash3, NULL, NULL));
   EXPECT_TRUE(base::DeleteFile(temp7, false));
 }
 
 }  // namespace extensions