Don't bother layout until first navigation is done.

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"
@@ skipping 10 matching lines @@
     SimTest();
     ~SimTest() override;
 
     void loadURL(const String& url);
 
     Document& document();
     WebViewImpl& webView();
     const SimWebViewClient& webViewClient() const;
     SimCompositor& compositor();
 
+    bool hadFirstLayout() const { return m_webViewClient.hadFirstLayout(); }
+
 private:
     SimNetwork m_network;
     SimCompositor m_compositor;
     SimWebViewClient m_webViewClient;
     FrameTestHelpers::WebViewHelper m_webViewHelper;
 };
 
 } // namespace blink
 
 #endif