Defer style recalc when inserting extension stylesheets.

Source/web/tests/WebDocumentTest.cpp

+// 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 "config.h"
+
+#include "public/web/WebDocument.h"
+
+#include "CSSPropertyNames.h"
+#include "core/dom/Document.h"
+#include "core/dom/NodeRenderStyle.h"
+#include "core/frame/LocalFrame.h"
+#include "core/html/HTMLElement.h"
+#include "core/rendering/style/RenderStyle.h"
+#include "platform/graphics/Color.h"
+#include "web/tests/FrameTestHelpers.h"
+
+#include <gtest/gtest.h>
+
+using WebCore::Color;
+using WebCore::Document;
+using WebCore::HTMLElement;
+using WebCore::RenderStyle;
+using blink::FrameTestHelpers::WebViewHelper;
+using blink::WebDocument;
+
+namespace {
+
+TEST(WebDocumentTest, InsertStyleSheet)
+{
+    WebViewHelper webViewHelper;
+    webViewHelper.initializeAndLoad("about:blank");

[rune, 2014/05/21 12:18:18]

See https://code.google.com/p/chromium/issues/detail?id=375728

Using this as a work-around as about:blank also contains a body element.

+
+    WebDocument webDoc = webViewHelper.webView()->mainFrame()->document();
+    Document* coreDoc = webViewHelper.webViewImpl()->page()->mainFrame()->document();
+
+    webDoc.insertStyleSheet("body { color: green }");
+
+    // Check insertStyleSheet did not cause a synchronous style recalc.
+    unsigned accessCount = coreDoc->styleEngine()->resolverAccessCount();
+    ASSERT_EQ(0U, accessCount);
+
+    HTMLElement* bodyElement = coreDoc->body();
+    ASSERT(bodyElement);
+
+    RenderStyle* style = bodyElement->renderStyle();
+    ASSERT(style);
+
+    // Inserted stylesheet not yet applied.
+    ASSERT_EQ(Color(0, 0, 0), style->visitedDependentColor(WebCore::CSSPropertyColor));
+
+    // Apply inserted stylesheet.
+    coreDoc->updateRenderTreeIfNeeded();
+
+    style = bodyElement->renderStyle();
+    ASSERT(style);
+
+    // Inserted stylesheet applied.
+    ASSERT_EQ(Color(0, 128, 0), style->visitedDependentColor(WebCore::CSSPropertyColor));
+}
+
+}