Don't bother layout until first navigation is done.

third_party/WebKit/Source/web/tests/DocumentLoadingRenderingTest.cpp

 // 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.
 
 #include "core/dom/Document.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "web/tests/sim/SimCompositor.h"
 #include "web/tests/sim/SimDisplayItemList.h"
 #include "web/tests/sim/SimRequest.h"
@@ skipping 273 matching lines @@
     // paint invalidation for every layer since frame2 painted them but skipped
     // painting the real content to avoid FOUC.
     cssResource.complete();
 
     // First frame where all frames are loaded, should paint the text in the
     // child frame.
     auto frame3 = compositor().beginFrame();
     EXPECT_TRUE(frame3.containsText());
 }
 
+TEST_F(DocumentLoadingRenderingTest, ShouldNotLayoutBeforeNavigation)
+{
+    EXPECT_TRUE(compositor().deferCommits());
+    EXPECT_FALSE(hadFirstLayout());
+
+    // Blink embedder may resize the WebView before navigation, but it shouldn't
+    // trigger empty layout.
+    webView().resize(WebSize(800, 600));
+    EXPECT_TRUE(compositor().deferCommits());
+    EXPECT_FALSE(hadFirstLayout());
+
+    // Blink embedder may set focus on the WebView before navigation,
+    // but it shouldn't trigger empty layout.
+    webView().setFocus(true);
+    EXPECT_TRUE(compositor().deferCommits());
+    EXPECT_FALSE(hadFirstLayout());
+}
+
 } // namespace blink