Add Autofill preview support for <select> input fields

Source/core/rendering/RenderListBox.cpp

Index: Source/core/rendering/RenderListBox.cpp
diff --git a/Source/core/rendering/RenderListBox.cpp b/Source/core/rendering/RenderListBox.cpp
index 37fade30333d46c3bbc9302f93134d910ae6e569..016cd795dea75f081cfb97d61f8fb2773bdafe15 100644
--- a/Source/core/rendering/RenderListBox.cpp
+++ b/Source/core/rendering/RenderListBox.cpp
@@ -340,6 +340,12 @@ void RenderListBox::addFocusRingRects(Vector<IntRect>& rects, const LayoutPoint&
 
     HTMLSelectElement* select = selectElement();
 
+    // Focus the previewed item.

[tkent, 2014/03/04 01:09:01]

How does it look like?  We need a rendering test.

+    if (select->suggestedIndex() >= 0) {
+        rects.append(pixelSnappedIntRect(itemBoundingBoxRect(additionalOffset, select->suggestedIndex())));
+        return;
+    }
+
     // Focus the last selected item.
     int selectedItem = select->activeSelectionEndListIndex();
     if (selectedItem >= 0) {
@@ -426,7 +432,7 @@ void RenderListBox::paintItemForeground(PaintInfo& paintInfo, const LayoutPoint&
     applyTextTransform(style(), itemText, ' ');
 
     Color textColor = element->renderStyle() ? resolveColor(element->renderStyle(), CSSPropertyColor) : resolveColor(CSSPropertyColor);
-    if (isOptionElement && toHTMLOptionElement(element)->selected()) {
+    if (isOptionElement && ((toHTMLOptionElement(element)->selected() && select->suggestedIndex() < 0) || listIndex == select->suggestedIndex())) {
         if (frame()->selection().isFocusedAndActive() && document().focusedElement() == node())
             textColor = RenderTheme::theme().activeListBoxSelectionForegroundColor();
         // Honor the foreground color for disabled items
@@ -460,7 +466,7 @@ void RenderListBox::paintItemBackground(PaintInfo& paintInfo, const LayoutPoint&
     HTMLElement* element = listItems[listIndex];
 
     Color backColor;
-    if (element->hasTagName(optionTag) && toHTMLOptionElement(element)->selected()) {
+    if (element->hasTagName(optionTag) && ((toHTMLOptionElement(element)->selected() && selectElement()->suggestedIndex() < 0) || listIndex == selectElement()->suggestedIndex())) {
         if (frame()->selection().isFocusedAndActive() && document().focusedElement() == node())
             backColor = RenderTheme::theme().activeListBoxSelectionBackgroundColor();
         else