Set overflow: auto in StyleResolver::styleForDocument.

third_party/WebKit/Source/web/tests/sim/SimTest.h

 // Copyright 2015 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.
 
 #ifndef SimTest_h
 #define SimTest_h
 
 #include "web/tests/FrameTestHelpers.h"
 #include "web/tests/sim/SimCompositor.h"
 #include "web/tests/sim/SimNetwork.h"
 #include "web/tests/sim/SimPage.h"
 #include "web/tests/sim/SimWebViewClient.h"
 #include <gtest/gtest.h>
 
 namespace blink {
 
 class WebViewImpl;
+class WebLocalFrameImpl;
 class Document;
 class LocalDOMWindow;
 
 class SimTest : public ::testing::Test {
  protected:
   SimTest();
   ~SimTest() override;
 
   void loadURL(const String& url);
 
   LocalDOMWindow& window();
   SimPage& page();
   Document& document();
   WebViewImpl& webView();
+  WebLocalFrameImpl& mainFrame();
   const SimWebViewClient& webViewClient() const;
   SimCompositor& compositor();
 
  private:
   SimNetwork m_network;
   SimCompositor m_compositor;
   SimWebViewClient m_webViewClient;
   SimPage m_page;
   FrameTestHelpers::WebViewHelper m_webViewHelper;
 };
 
 }  // namespace blink
 
 #endif