Add Autofill preview support for <select> input fields

Source/core/html/HTMLSelectElement.cpp

Index: Source/core/html/HTMLSelectElement.cpp
diff --git a/Source/core/html/HTMLSelectElement.cpp b/Source/core/html/HTMLSelectElement.cpp
index 6be5c079cccbc348acd6f9a648b0a4354870d240..6349335eedd54dc357abc420cf9b3a050469bd89 100644
--- a/Source/core/html/HTMLSelectElement.cpp
+++ b/Source/core/html/HTMLSelectElement.cpp
@@ -253,6 +253,35 @@ void HTMLSelectElement::setValue(const String &value)
     setSelectedIndex(-1);
 }
 
+String HTMLSelectElement::suggestedValue() const
+{
+    return m_suggestedValue;

[keishi, 2014/03/13 04:47:50]

It doesn't matter yet, but, HTMLInputElement seems to be returning the sanitized
value. Maybe we should return an empty string if the option with that value
doesn't exist.

[ziran.sun, 2014/03/13 11:20:52]

Done.

+}
+
+void HTMLSelectElement::setSuggestedValue(const String& value)
+{
+    m_suggestedValue = value;
+
+    if (value.isNull()) {
+        setSuggestedIndex(-1);
+        return;
+    }
+
+    const Vector<HTMLElement*>& items = listItems();
+    unsigned optionIndex = 0;
+    for (unsigned i = 0; i < items.size(); i++) {
+        if (items[i]->hasLocalName(optionTag)) {
+            if (toHTMLOptionElement(items[i])->value() == value) {
+                setSuggestedIndex(optionIndex);
+                return;
+            }
+            optionIndex++;
+        }
+    }
+
+    setSuggestedIndex(-1);
+}
+
 bool HTMLSelectElement::isPresentationAttribute(const QualifiedName& name) const
 {
     if (name == alignAttr) {
@@ -795,6 +824,24 @@ void HTMLSelectElement::setSelectedIndex(int index)
     selectOption(index, DeselectOtherOptions);
 }
 
+int HTMLSelectElement::suggestedIndex() const
+{
+    return m_suggestedIndex;
+}
+
+void HTMLSelectElement::setSuggestedIndex(int suggestedIndex)
+{
+    m_suggestedIndex = suggestedIndex;
+
+    if (RenderObject* renderer = this->renderer())  {
+        renderer->updateFromElement();
+        if (renderer->isListBox())
+            toRenderListBox(renderer)->scrollToRevealElementAtListIndex(suggestedIndex);
+    }
+
+    setNeedsValidityCheck();
+}
+
 void HTMLSelectElement::optionSelectionStateChanged(HTMLOptionElement* option, bool optionIsSelected)
 {
     ASSERT(option->ownerSelectElement() == this);