Fix for ::selection pseudo element to work on input elements

Source/core/rendering/RenderObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1769 matching lines @@
     return !isInert() && !(style()->userSelect() == SELECT_NONE && style()->userModify() == READ_ONLY);
 }
 
 Color RenderObject::selectionBackgroundColor() const
 {
     if (!isSelectable())
         return Color::transparent;
 
     if (RefPtr<RenderStyle> pseudoStyle = getUncachedPseudoStyle(PseudoStyleRequest(SELECTION)))
         return resolveColor(pseudoStyle.get(), CSSPropertyBackgroundColor).blendWithWhite();
+
+    // If the element is in shadow tree of input element, then get the PseudoStyle
+    // from the input element.
+    if (node() && node()->shadowHost()) {
+        RenderObject* shadowHostRenderer = node()->shadowHost()->renderer();
+        if (shadowHostRenderer->isTextControl()) {

[ojan, 2014/04/09 01:57:53]

Special casing text controls is not right. For example, this won't fix buttons:
<input type="button" value="button" style="-webkit-user-select:auto">

Also, the way I would expect this code to work is that you'd set the pseudoStyle
based of whether it's in a shadowHost. That way you wouldn't need to duplicate
the resolveColor line.

That all said, I'm not really sure what the right fix is. I defer to
tkent/esprehn on what the right way to target user-agent shadow hosts is.

+            if (RefPtr<RenderStyle> pseudoStyle = shadowHostRenderer->getUncachedPseudoStyle(PseudoStyleRequest(SELECTION)))
+                return resolveColor(pseudoStyle.get(), CSSPropertyBackgroundColor).blendWithWhite();
+        }
+    }
+
     return frame()->selection().isFocusedAndActive() ?
         RenderTheme::theme().activeSelectionBackgroundColor() :
         RenderTheme::theme().inactiveSelectionBackgroundColor();
 }
 
 Color RenderObject::selectionColor(int colorProperty) const
 {
     // If the element is unselectable, or we are only painting the selection,
     // don't override the foreground color with the selection foreground color.
     if (!isSelectable() || (frame()->view()->paintBehavior() & PaintBehaviorSelectionOnly))
         return resolveColor(colorProperty);
 
     if (RefPtr<RenderStyle> pseudoStyle = getUncachedPseudoStyle(PseudoStyleRequest(SELECTION)))
         return resolveColor(pseudoStyle.get(), colorProperty);
+
+    // If the element is in shadow tree of input element, then get the PseudoStyle
+    // from the input element.
+    if (node() && node()->shadowHost()) {
+        RenderObject* shadowHostRenderer = node()->shadowHost()->renderer();
+        if (shadowHostRenderer->isTextControl()) {
+            if (RefPtr<RenderStyle> pseudoStyle = shadowHostRenderer->getUncachedPseudoStyle(PseudoStyleRequest(SELECTION)))
+                return resolveColor(pseudoStyle.get(), colorProperty);
+        }
+    }
+
     if (!RenderTheme::theme().supportsSelectionForegroundColors())
         return resolveColor(colorProperty);
     return frame()->selection().isFocusedAndActive() ?
         RenderTheme::theme().activeSelectionForegroundColor() :
         RenderTheme::theme().inactiveSelectionForegroundColor();
 }
 
 Color RenderObject::selectionForegroundColor() const
 {
     return selectionColor(CSSPropertyWebkitTextFillColor);
@@ skipping 1561 matching lines @@
 {
     if (object1) {
         const WebCore::RenderObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showRenderTreeAndMark(object1, "*", object2, "-", 0);
     }
 }
 
 #endif