AX: Make picker indicator elements focusable if accessibility is enabled.

Source/core/html/shadow/PickerIndicatorElement.cpp

Index: Source/core/html/shadow/PickerIndicatorElement.cpp
diff --git a/Source/core/html/shadow/PickerIndicatorElement.cpp b/Source/core/html/shadow/PickerIndicatorElement.cpp
index 17115a47ea6152a2fa426085993a61f91d619ff6..342a19ecfca2822ff74cb625cb0c1f6f91031304 100644
--- a/Source/core/html/shadow/PickerIndicatorElement.cpp
+++ b/Source/core/html/shadow/PickerIndicatorElement.cpp
@@ -33,10 +33,15 @@
 #include "core/html/shadow/PickerIndicatorElement.h"
 
 #include "core/events/Event.h"
+#include "core/events/KeyboardEvent.h"
+#include "core/frame/Settings.h"
 #include "core/html/shadow/ShadowElementNames.h"
 #include "core/page/Chrome.h"
 #include "core/page/Page.h"
 #include "core/rendering/RenderDetailsMarker.h"
+#include "platform/LayoutTestSupport.h"
+#include "platform/text/PlatformLocale.h"
+#include "public/platform/WebLocalizedString.h"
 #include "wtf/TemporaryChange.h"
 
 using namespace WTF::Unicode;
@@ -81,6 +86,12 @@ void PickerIndicatorElement::defaultEventHandler(Event* event)
     if (event->type() == EventTypeNames::click) {
         openPopup();
         event->setDefaultHandled();
+    } else if (event->type() == EventTypeNames::keypress && event->isKeyboardEvent()) {
+        int charCode = toKeyboardEvent(event)->charCode();
+        if (charCode == ' ' || charCode == '\r') {
+            openPopup();
+            event->setDefaultHandled();
+        }
     }
 
     if (!event->defaultHandled())
@@ -162,6 +173,26 @@ bool PickerIndicatorElement::isPickerIndicatorElement() const
     return true;
 }
 
+Node::InsertionNotificationRequest PickerIndicatorElement::insertedInto(ContainerNode* insertionPoint)
+{
+    HTMLDivElement::insertedInto(insertionPoint);
+    return InsertionShouldCallDidNotifySubtreeInsertions;
+}
+
+void PickerIndicatorElement::didNotifySubtreeInsertionsToDocument()
+{
+    if (!document().settings() || !document().settings()->accessibilityEnabled())
+        return;
+    // Don't make this focusable if we are in layout tests in order to avoid to
+    // break existing tests.
+    // FIXME: We should have a way to disable accessibility in layout tests.
+    if (LayoutTestSupport::isRunningLayoutTest())
+        return;
+    setAttribute(tabindexAttr, "0");
+    setAttribute(aria_labelAttr, AtomicString(locale().queryString(WebLocalizedString::AXShowPickerButton)));
+    setAttribute(roleAttr, "button");
+}
+
 void PickerIndicatorElement::trace(Visitor* visitor)
 {
     visitor->trace(m_pickerIndicatorOwner);