Add TestBrowserThreadBundle into RenderViewHostTestHarness. Kill some unnecessary real threads.

content/public/test/test_renderer_host.cc

Index: content/public/test/test_renderer_host.cc
diff --git a/content/public/test/test_renderer_host.cc b/content/public/test/test_renderer_host.cc
index 9a1cc856c58935bdf4b447e44d833e7b112eb315..c9b4e6d6cc4cc82224f4be84756bc0d55c242115 100644
--- a/content/public/test/test_renderer_host.cc
+++ b/content/public/test/test_renderer_host.cc
@@ -72,7 +72,9 @@ RenderViewHostTestEnabler::~RenderViewHostTestEnabler() {
 
 // RenderViewHostTestHarness --------------------------------------------------
 
-RenderViewHostTestHarness::RenderViewHostTestHarness() : contents_(NULL) {
+RenderViewHostTestHarness::RenderViewHostTestHarness()
+  : contents_(NULL),
+    real_threads_mask_(TestBrowserThreadBundle::NO_REAL_THREAD) {
 }
 
 RenderViewHostTestHarness::~RenderViewHostTestHarness() {
@@ -155,11 +157,14 @@ void RenderViewHostTestHarness::FailedReload() {
 }
 
 void RenderViewHostTestHarness::SetUp() {
+  thread_bundle_.reset(new TestBrowserThreadBundle(real_threads_mask_));
+
 #if defined(OS_WIN)
   ole_initializer_.reset(new ui::ScopedOleInitializer());
 #endif
 #if defined(USE_AURA)
-  aura_test_helper_.reset(new aura::test::AuraTestHelper(&message_loop_));
+  aura_test_helper_.reset(
+      new aura::test::AuraTestHelper(base::MessageLoopForUI::current()));
   aura_test_helper_->SetUp();
 #endif
   SetContents(CreateTestWebContents());
@@ -178,13 +183,19 @@ void RenderViewHostTestHarness::TearDown() {
   if (rvh_test_enabler_.rph_factory_)
     rvh_test_enabler_.rph_factory_.reset();
 
-  // Release the browser context on the UI thread.
-  message_loop_.DeleteSoon(FROM_HERE, browser_context_.release());
+  // Release the browser context by posting itself on the end of the task
+  // queue. This is preferable to immediate deletion because it will behave
+  // properly if the |rph_factory_| reset above enqueued any tasks which
+  // depend on |browser_context_|.
+  BrowserThread::DeleteSoon(content::BrowserThread::UI,
+                            FROM_HERE,
+                            browser_context_.release());
   base::RunLoop().RunUntilIdle();
 
 #if defined(OS_WIN)
   ole_initializer_.reset();
 #endif
+  thread_bundle_.reset();
 }
 
 void RenderViewHostTestHarness::SetRenderProcessHostFactory(