Implement aria properties setsize and posinset.

public/web/WebAXObject.h

Index: public/web/WebAXObject.h
diff --git a/public/web/WebAXObject.h b/public/web/WebAXObject.h
index c117025cca1d71a97b5b3946fd249b28b0476a2f..ef9d4ea77c822f89b08c28bed5cbf856b8ddb9cc 100644
--- a/public/web/WebAXObject.h
+++ b/public/web/WebAXObject.h
@@ -121,7 +121,6 @@ public:
     BLINK_EXPORT bool ariaFlowTo(WebVector<WebAXObject>& flowToElements) const;
     BLINK_EXPORT bool ariaHasPopup() const;
     BLINK_EXPORT bool ariaLabelledby(WebVector<WebAXObject>& labelledbyElements) const;
-    BLINK_EXPORT bool isMultiline() const;
     BLINK_EXPORT bool ariaOwns(WebVector<WebAXObject>& ownsElements) const;
     BLINK_EXPORT WebRect boundingBoxRect() const;
     BLINK_EXPORT bool canvasHasFallbackContent() const;
@@ -135,13 +134,16 @@ public:
     BLINK_EXPORT int headingLevel() const;
     BLINK_EXPORT int hierarchicalLevel() const;
     BLINK_EXPORT WebAXObject hitTest(const WebPoint&) const;
+    BLINK_EXPORT bool isMultiline() const;
     BLINK_EXPORT WebString keyboardShortcut() const;
     BLINK_EXPORT WebString placeholder() const;
+    BLINK_EXPORT int posInSet() const;
     BLINK_EXPORT WebAXRole role() const;
     BLINK_EXPORT unsigned selectionEnd() const;
     BLINK_EXPORT unsigned selectionEndLineNumber() const;
     BLINK_EXPORT unsigned selectionStart() const;
     BLINK_EXPORT unsigned selectionStartLineNumber() const;
+    BLINK_EXPORT int setSize() const;
     BLINK_EXPORT WebString stringValue() const;
     BLINK_EXPORT WebString title() const;
     BLINK_EXPORT WebString language() const;