[Mac] Fix a leak in CookiesWindowControllerTest by giving BrowserTestHelper a fake IO thread.

chrome/browser/cocoa/cookies_window_controller_unittest.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "app/l10n_util_mac.h"
 #include "app/tree_model.h"
 #import "base/scoped_nsobject.h"
 #include "base/scoped_ptr.h"
@@ skipping 33 matching lines @@
 }
 - (TreeModelNode*)treeNode {
   return testNode_;
 }
 @end
 
 namespace {
 
 class CookiesWindowControllerTest : public CocoaTest {
  public:
-  CookiesWindowControllerTest()
-      : io_thread_(ChromeThread::IO, MessageLoop::current()) {}
 
   virtual void SetUp() {
     CocoaTest::SetUp();
     TestingProfile* profile = browser_helper_.profile();
     profile->CreateRequestContext();
     database_helper_ = new MockBrowsingDataDatabaseHelper(profile);
     local_storage_helper_ = new MockBrowsingDataLocalStorageHelper(profile);
     appcache_helper_ = new MockBrowsingDataAppCacheHelper(profile);
     controller_.reset(
         [[CookiesWindowController alloc] initWithProfile:profile
@@ skipping 11 matching lines @@
     return [controller_ modelObserver]->CocoaNodeFromTreeNode(node);
   }
 
   CocoaCookieTreeNode* FindCocoaNode(TreeModelNode* node,
                                      CocoaCookieTreeNode* start) {
     return [controller_ modelObserver]->FindCocoaNode(node, start);
   }
 
  protected:
   BrowserTestHelper browser_helper_;
-  // Need an IO thread to not leak from TestingProfile::CreateRequestContext().
-  ChromeThread io_thread_;
   scoped_nsobject<CookiesWindowController> controller_;
   MockBrowsingDataDatabaseHelper* database_helper_;
   MockBrowsingDataLocalStorageHelper* local_storage_helper_;
   MockBrowsingDataAppCacheHelper* appcache_helper_;
 };
 
 TEST_F(CookiesWindowControllerTest, Construction) {
   std::vector<SkBitmap> skia_icons;
   [controller_ treeModel]->GetIcons(&skia_icons);
 
@@ skipping 636 matching lines @@
   // Local Storage --> origin2.
   node = [[node children] lastObject];
   EXPECT_TRUE([@"origin2" isEqualToString:[node title]]);
   EXPECT_EQ(kCocoaCookieDetailsTypeTreeLocalStorage, [node nodeType]);
   EXPECT_TRUE([@"origin2" isEqualToString:[[node details] domain]]);
   EXPECT_TRUE([[node details] lastModified]);
   EXPECT_TRUE([[node details] fileSize]);
 }
 
 }  // namespace