Don't bother layout until first navigation is done.

third_party/WebKit/Source/web/WebLocalFrameImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1828 matching lines @@
 
     if (!frame()->document() || !frame()->page())
         return;
 
     RefPtrWillBeRawPtr<Document> ownerDocument(frame()->document());
 
     // Protect privileged pages against bookmarklets and other javascript manipulations.
     if (SchemeRegistry::shouldTreatURLSchemeAsNotAllowingJavascriptURLs(frame()->document()->url().protocol()))
         return;
 
+    ownerDocument->markNonInitialEmptyDocument();
+
     String script = decodeURLEscapeSequences(url.string().substring(strlen("javascript:")));
     UserGestureIndicator gestureIndicator(DefinitelyProcessingNewUserGesture);
     v8::HandleScope handleScope(toIsolate(frame()));
     v8::Local<v8::Value> result = frame()->script().executeScriptInMainWorldAndReturnValue(ScriptSourceCode(script));
     if (result.IsEmpty() || !result->IsString())
         return;
     String scriptResult = toCoreString(v8::Local<v8::String>::Cast(result));
     if (!frame()->navigationScheduler().locationChangePending())
         frame()->loader().replaceDocumentWhileExecutingJavaScriptURL(scriptResult, ownerDocument.get());
 }
@@ skipping 327 matching lines @@
         return WebSandboxFlags::None;
     return static_cast<WebSandboxFlags>(frame()->loader().effectiveSandboxFlags());
 }
 
 void WebLocalFrameImpl::forceSandboxFlags(WebSandboxFlags flags)
 {
     frame()->loader().forceSandboxFlags(static_cast<SandboxFlags>(flags));
 }
 
 } // namespace blink