Have getElementsByClassName() / getElementsByTagName*() return an HTMLCollection

Source/core/dom/Element.idl

Index: Source/core/dom/Element.idl
diff --git a/Source/core/dom/Element.idl b/Source/core/dom/Element.idl
index 5ce30ecc1616405165346b8a6a125b30ac71fdc9..e4e3fb94bee6a8757c6bb50dc5476ce36c92009f 100644
--- a/Source/core/dom/Element.idl
+++ b/Source/core/dom/Element.idl
@@ -32,7 +32,7 @@
     [MeasureAs=ElementGetAttributeNode] Attr getAttributeNode([Default=Undefined] optional DOMString name); // Removed from DOM4.
     [RaisesException, CustomElementCallbacks, MeasureAs=ElementSetAttributeNode] Attr setAttributeNode([Default=Undefined, StrictTypeChecking] optional Attr newAttr); // Removed from DOM4.
     [RaisesException, CustomElementCallbacks, MeasureAs=ElementRemoveAttributeNode] Attr removeAttributeNode([Default=Undefined, StrictTypeChecking] optional Attr oldAttr); // Removed from DOM4.
-    [PerWorldBindings] NodeList getElementsByTagName(DOMString name);
+    [PerWorldBindings] HTMLCollection getElementsByTagName(DOMString name);
 
     [PerWorldBindings] readonly attribute NamedNodeMap     attributes;
     [MeasureAs=HasAttributes] boolean hasAttributes();
@@ -42,7 +42,7 @@
     DOMString getAttributeNS([TreatNullAs=NullString] DOMString namespaceURI, DOMString localName);
     [RaisesException, CustomElementCallbacks] void setAttributeNS([TreatNullAs=NullString] DOMString namespaceURI, DOMString qualifiedName, DOMString value);
     [CustomElementCallbacks] void removeAttributeNS([TreatNullAs=NullString] DOMString namespaceURI, DOMString localName);
-    NodeList getElementsByTagNameNS([TreatNullAs=NullString] DOMString namespaceURI, DOMString localName);
+    HTMLCollection getElementsByTagNameNS([TreatNullAs=NullString] DOMString namespaceURI, DOMString localName);
     [MeasureAs=ElementGetAttributeNodeNS] Attr getAttributeNodeNS([TreatNullAs=NullString,Default=Undefined] optional DOMString namespaceURI,
                                                                   [Default=Undefined] optional DOMString localName); // Removed from DOM4.
     [RaisesException, CustomElementCallbacks, MeasureAs=ElementSetAttributeNodeNS] Attr setAttributeNodeNS([Default=Undefined, StrictTypeChecking] optional Attr newAttr); // Removed from DOM4.
@@ -86,7 +86,7 @@
     void scrollByPages([Default=Undefined] optional long pages);
 
     // HTML 5
-    NodeList getElementsByClassName(DOMString classNames);
+    HTMLCollection getElementsByClassName(DOMString classNames);
     [TreatNullAs=NullString, CustomElementCallbacks, PerWorldBindings, ActivityLogging=SetterForIsolatedWorlds, RaisesException=Setter] attribute DOMString innerHTML;
     [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter] attribute DOMString outerHTML;
     [CustomElementCallbacks, RaisesException] void insertAdjacentHTML(DOMString where, DOMString html);