Revert of Moves ash content specific tests into ash_content_unittests

ash/test/ash_test_base.cc

Index: ash/test/ash_test_base.cc
diff --git a/ash/test/ash_test_base.cc b/ash/test/ash_test_base.cc
index ecf6cd36734aa538d58d6604e7cfd5fda5a6b72c..767a0add927b5f657700fb607c811a25e97dadf4 100644
--- a/ash/test/ash_test_base.cc
+++ b/ash/test/ash_test_base.cc
@@ -16,7 +16,6 @@
 #include "ash/ime/input_method_event_handler.h"
 #include "ash/shell.h"
 #include "ash/shell/toplevel_window.h"
-#include "ash/test/ash_test_environment.h"
 #include "ash/test/ash_test_helper.h"
 #include "ash/test/display_manager_test_api.h"
 #include "ash/test/test_session_state_delegate.h"
@@ -103,11 +102,10 @@
   gfx::InitializeThreadedX11();
 #endif
 
-  ash_test_environment_ = AshTestEnvironment::Create();
-
+  thread_bundle_.reset(new content::TestBrowserThreadBundle);
   // Must initialize |ash_test_helper_| here because some tests rely on
   // AshTestBase methods before they call AshTestBase::SetUp().
-  ash_test_helper_.reset(new AshTestHelper(ash_test_environment_.get()));
+  ash_test_helper_.reset(new AshTestHelper(base::MessageLoopForUI::current()));
 }
 
 AshTestBase::~AshTestBase() {