Introduce HTMLDataListOptionsCollection subclass for HTMLCollection

Source/core/html/HTMLInputElement.cpp

Index: Source/core/html/HTMLInputElement.cpp
diff --git a/Source/core/html/HTMLInputElement.cpp b/Source/core/html/HTMLInputElement.cpp
index 58ffff2bb0ff639cea445a00d641317a7aa9ba18..fc2a3e422c5c0a589dea54b6373a6d32899b76b4 100644
--- a/Source/core/html/HTMLInputElement.cpp
+++ b/Source/core/html/HTMLInputElement.cpp
@@ -57,6 +57,7 @@
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLCollection.h"
 #include "core/html/HTMLDataListElement.h"
+#include "core/html/HTMLDataListOptionsCollection.h"
 #include "core/html/HTMLFormElement.h"
 #include "core/html/HTMLImageLoader.h"
 #include "core/html/HTMLOptionElement.h"
@@ -1519,8 +1520,8 @@ bool HTMLInputElement::hasValidDataListOptions() const
     HTMLDataListElement* dataList = this->dataList();
     if (!dataList)
         return false;
-    RefPtrWillBeRawPtr<HTMLCollection> options = dataList->options();
-    for (unsigned i = 0; HTMLOptionElement* option = toHTMLOptionElement(options->item(i)); ++i) {
+    RefPtrWillBeRawPtr<HTMLDataListOptionsCollection> options = dataList->options();
+    for (unsigned i = 0; HTMLOptionElement* option = options->item(i); ++i) {
         if (isValidValue(option->value()))
             return true;
     }
@@ -1835,8 +1836,8 @@ bool HTMLInputElement::setupDateTimeChooserParameters(DateTimeChooserParameters&
     parameters.doubleValue = m_inputType->valueAsDouble();
     parameters.isAnchorElementRTL = m_inputType->computedTextDirection() == RTL;
     if (HTMLDataListElement* dataList = this->dataList()) {
-        RefPtrWillBeRawPtr<HTMLCollection> options = dataList->options();
-        for (unsigned i = 0; HTMLOptionElement* option = toHTMLOptionElement(options->item(i)); ++i) {
+        RefPtrWillBeRawPtr<HTMLDataListOptionsCollection> options = dataList->options();
+        for (unsigned i = 0; HTMLOptionElement* option = options->item(i); ++i) {
             if (!isValidValue(option->value()))
                 continue;
             DateTimeSuggestion suggestion;