Support getComputedStyle for non-rendered pseudo elements.

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 2380 matching lines @@
     if (!hasRareData() && size == defaultMinimumSizeForResizing())
         return;
     ensureElementRareData().setMinimumSizeForResizing(size);
 }
 
 RenderStyle* Element::computedStyle(PseudoId pseudoElementSpecifier)
 {
     if (PseudoElement* element = pseudoElement(pseudoElementSpecifier))
         return element->computedStyle();
 
+    if (!inActiveDocument()) {
+        // FIXME: Try to do better than this. Ensure that styleForElement() works for elements that are not in the
+        // document tree and figure out when to destroy the computed style for such elements.
+        return 0;
+    }
+
     // FIXME: Find and use the renderer from the pseudo element instead of the actual element so that the 'length'
     // properties, which are only known by the renderer because it did the layout, will be correct and so that the
     // values returned for the ":selection" pseudo-element will be correct.
-    if (RenderStyle* usedStyle = renderStyle()) {
-        if (pseudoElementSpecifier) {
-            RenderStyle* cachedPseudoStyle = usedStyle->getCachedPseudoStyle(pseudoElementSpecifier);
-            return cachedPseudoStyle ? cachedPseudoStyle : usedStyle;
-         } else
-            return usedStyle;
+    RenderStyle* elementStyle = renderStyle();
+    if (!elementStyle) {
+        ElementRareData& rareData = ensureElementRareData();
+        if (!rareData.computedStyle())
+            rareData.setComputedStyle(document().styleForElementIgnoringPendingStylesheets(this));
+        elementStyle = rareData.computedStyle();
     }
 
-    if (!inActiveDocument())
-        // FIXME: Try to do better than this. Ensure that styleForElement() works for elements that are not in the
-        // document tree and figure out when to destroy the computed style for such elements.
-        return 0;
+    if (!pseudoElementSpecifier)
+        return elementStyle;
 
-    ElementRareData& rareData = ensureElementRareData();
-    if (!rareData.computedStyle())
-        rareData.setComputedStyle(document().styleForElementIgnoringPendingStylesheets(this));
-    return pseudoElementSpecifier ? rareData.computedStyle()->getCachedPseudoStyle(pseudoElementSpecifier) : rareData.computedStyle();
+    if (RenderStyle* pseudoElementStyle = elementStyle->getCachedPseudoStyle(pseudoElementSpecifier))
+        return pseudoElementStyle;
+
+    RefPtr<RenderStyle> result = document().ensureStyleResolver().pseudoStyleForElement(this, PseudoStyleRequest(pseudoElementSpecifier, PseudoStyleRequest::ForComputedStyle), elementStyle);
+    ASSERT(result);
+    return elementStyle->addCachedPseudoStyle(result.release());
 }
 
 AtomicString Element::computeInheritedLanguage() const
 {
     const Node* n = this;
     AtomicString value;
     // The language property is inherited, so we iterate over the parents to find the first language.
     do {
         if (n->isElementNode()) {
             if (const ElementData* elementData = toElement(n)->elementData()) {
@@ skipping 817 matching lines @@
         return v8::Handle<v8::Object>();
 
     wrapper->SetPrototype(binding->prototype());
 
     wrapperType->refObject(toScriptWrappableBase());
     V8DOMWrapper::associateObjectWithWrapperNonTemplate(this, wrapperType, wrapper, isolate);
     return wrapper;
 }
 
 } // namespace blink