Remove unused paintScrollbarThumb impl.

content/shell/renderer/test_runner/test_interfaces.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 "content/shell/renderer/test_runner/test_interfaces.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 165 matching lines @@
   return proxy_;
 }
 
 const std::vector<WebTestProxyBase*>& TestInterfaces::GetWindowList() {
   return window_list_;
 }
 
 blink::WebThemeEngine* TestInterfaces::GetThemeEngine() {
   if (!test_runner_->UseMockTheme())
     return 0;
-#if defined(OS_MACOSX)
-  if (!theme_engine_.get())
-    theme_engine_.reset(new MockWebThemeEngineMac());
-#else
   if (!theme_engine_.get())
     theme_engine_.reset(new MockWebThemeEngine());
-#endif
   return theme_engine_.get();
 }
 
 }  // namespace content