Enable accessible name of a control to include multiple <label> elements.

third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp b/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
index 4ee9228e6fad4586fd15b2573edf91227fc9e4ff..f65f6070890e62a03c70356fe5823a0d01b0f8f0 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp
@@ -52,6 +52,7 @@
 #include "core/html/HTMLTableRowElement.h"
 #include "core/html/HTMLTableSectionElement.h"
 #include "core/html/HTMLTextAreaElement.h"
+#include "core/html/LabelsNodeList.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/html/shadow/MediaControlElements.h"
 #include "core/layout/LayoutBlockFlow.h"
@@ -645,24 +646,6 @@ bool AXNodeObject::isGenericFocusableElement() const
     return true;
 }
 
-HTMLLabelElement* AXNodeObject::labelForElement(const Element* element) const
-{
-    if (!element->isHTMLElement() || !toHTMLElement(element)->isLabelable())
-        return 0;
-
-    const AtomicString& id = element->getIdAttribute();
-    if (!id.isEmpty()) {
-        if (HTMLLabelElement* labelFor = element->treeScope().labelElementForId(id))
-            return labelFor;
-    }
-
-    HTMLLabelElement* labelWrappedElement = Traversal<HTMLLabelElement>::firstAncestor(*element);
-    if (labelWrappedElement && labelWrappedElement->control() == toLabelableElement(element))
-        return labelWrappedElement;
-
-    return 0;
-}
-
 AXObject* AXNodeObject::menuButtonForMenu() const
 {
     Element* menuItem = menuItemElementForMenu();
@@ -1669,7 +1652,7 @@ String AXNodeObject::textAlternative(bool recursive, bool inAriaLabelledByTraver
 
     nameFrom = AXNameFromUninitialized;
 
-    if (foundTextAlternative) {
+    if (nameSources && foundTextAlternative) {
         for (size_t i = 0; i < nameSources->size(); ++i) {
             if (!(*nameSources)[i].text.isNull() && !(*nameSources)[i].superseded) {
                 NameSource& nameSource = (*nameSources)[i];
@@ -1763,9 +1746,8 @@ bool AXNodeObject::nameFromLabelElement() const
     HTMLElement* htmlElement = nullptr;
     if (getNode()->isHTMLElement())
         htmlElement = toHTMLElement(getNode());
-    if (htmlElement && htmlElement->isLabelable()) {
-        HTMLLabelElement* label = labelForElement(htmlElement);
-        if (label)
+    if (htmlElement && isLabelableElement(htmlElement)) {
+        if (toLabelableElement(htmlElement)->labels() && toLabelableElement(htmlElement)->labels()->length() > 0)
             return true;
     }
 
@@ -2232,39 +2214,41 @@ String AXNodeObject::nativeTextAlternative(AXObjectSet& visited, AXNameFrom& nam
     HTMLElement* htmlElement = nullptr;
     if (getNode()->isHTMLElement())
         htmlElement = toHTMLElement(getNode());
+
     if (htmlElement && htmlElement->isLabelable()) {
-        // label
         nameFrom = AXNameFromRelatedElement;
         if (nameSources) {
             nameSources->append(NameSource(*foundTextAlternative));
             nameSources->last().type = nameFrom;
             nameSources->last().nativeSource = AXTextFromNativeHTMLLabel;
         }
-        HTMLLabelElement* label = labelForElement(htmlElement);
-        if (label) {
-            AXObject* labelAXObject = axObjectCache().getOrCreate(label);
-            // Avoid an infinite loop for label wrapped
-            if (labelAXObject && !visited.contains(labelAXObject)) {
-                textAlternative = recursiveTextAlternative(*labelAXObject, false, visited);
 
-                if (relatedObjects) {
-                    localRelatedObjects.append(new NameSourceRelatedObject(labelAXObject, textAlternative));
-                    *relatedObjects = localRelatedObjects;
-                    localRelatedObjects.clear();
+        LabelsNodeList* labels = toLabelableElement(htmlElement)->labels();
+        if (labels && labels->length() > 0) {
+            HeapVector<Member<Element>> labelElements;
+            for (unsigned labelIndex = 0; labelIndex < labels->length(); ++labelIndex) {
+                Element* label = labels->item(labelIndex);
+                if (nameSources) {
+                    if (label->getAttribute(forAttr) == htmlElement->getIdAttribute())
+                        nameSources->last().nativeSource = AXTextFromNativeHTMLLabelFor;
+                    else
+                        nameSources->last().nativeSource = AXTextFromNativeHTMLLabelWrapped;
                 }
+                labelElements.append(label);
+            }
 
+            textAlternative = textFromElements(false, visited, labelElements, relatedObjects);
+            if (!textAlternative.isNull()) {
+                *foundTextAlternative = true;
                 if (nameSources) {
                     NameSource& source = nameSources->last();
                     source.relatedObjects = *relatedObjects;
                     source.text = textAlternative;
-                    if (label->getAttribute(forAttr) == htmlElement->getIdAttribute())
-                        source.nativeSource = AXTextFromNativeHTMLLabelFor;
-                    else
-                        source.nativeSource = AXTextFromNativeHTMLLabelWrapped;
-                    *foundTextAlternative = true;
                 } else {
                     return textAlternative;
                 }
+            } else if (nameSources) {
+                nameSources->last().invalid = true;
             }
         }
     }