Add TestBrowserThreadBundle into RenderViewHostTestHarness. Kill some unnecessary real threads.

chrome/browser/password_manager/password_generation_manager_unittest.cc

Index: chrome/browser/password_manager/password_generation_manager_unittest.cc
diff --git a/chrome/browser/password_manager/password_generation_manager_unittest.cc b/chrome/browser/password_manager/password_generation_manager_unittest.cc
index e474e03dd7d9a6ae9787634a76e3c6d024d6c7ca..c77ab493853b048ed5256b698e2d2eba9cac591f 100644
--- a/chrome/browser/password_manager/password_generation_manager_unittest.cc
+++ b/chrome/browser/password_manager/password_generation_manager_unittest.cc
@@ -42,19 +42,14 @@ class TestPasswordGenerationManager : public PasswordGenerationManager {
 };
 
 class PasswordGenerationManagerTest : public ChromeRenderViewHostTestHarness {
- public:
-  PasswordGenerationManagerTest()
-      : ChromeRenderViewHostTestHarness(),
-        ui_thread_(content::BrowserThread::UI, &message_loop_),
-        io_thread_(content::BrowserThread::IO) {}
-
+ protected:
   virtual void SetUp() OVERRIDE {
     TestingProfile* profile = CreateProfile();
     profile->CreateRequestContext();
     browser_context_.reset(profile);
 
+    SetRealThreadMask(content::TestBrowserThreadBundle::REAL_IO_THREAD);
     ChromeRenderViewHostTestHarness::SetUp();
-    io_thread_.StartIOThread();
 
     password_generation_manager_.reset(
         new TestPasswordGenerationManager(web_contents()));
@@ -72,10 +67,6 @@ class PasswordGenerationManagerTest : public ChromeRenderViewHostTestHarness {
     password_generation_manager_->UpdateState(NULL, new_renderer);
   }
 
- protected:
-  content::TestBrowserThread ui_thread_;
-  content::TestBrowserThread io_thread_;
-
   scoped_ptr<TestPasswordGenerationManager> password_generation_manager_;
 };