Bug 1277090 - getElementAttribute() has to only return attributes. r=ato

Formerly getElementAttribute() has returned a mix of attributes and
properties. Since getElementProperty() has been added, there is no
need anymore for getElementAttribute() to return conflated data.

MozReview-Commit-ID: 29saWd9PsOX

--HG--
extra : rebase_source : e1dece7586c9b22320db406cfd60d211195f5f18

testing/marionette/client/marionette_driver/marionette.py

@@ -69,8 +69,14 @@ class HTMLElement(object):
         """Returns the requested property, or None if the property is
         not set.
         """
-        body = {"id": self.id, "name": name}
-        return self.marionette._send_message("getElementProperty", body, key="value")
+        try:
+            body = {"id": self.id, "name": name}
+            return self.marionette._send_message("getElementProperty", body, key="value")
+        except errors.UnknownCommandException:
+            # Keep backward compatibility for code which uses get_attribute() to
+            # also retrieve element properties.
+            # Remove when Firefox 55 is stable.
+            return self.get_attribute(name)
 
     def click(self):
         self.marionette._send_message("clickElement", {"id": self.id})

testing/marionette/driver.js

@@ -1842,7 +1842,8 @@ GeckoDriver.prototype.getElementAttribute = function*(cmd, resp) {
     case Context.CHROME:
       let win = this.getCurrentWindow();
       let el = this.curBrowser.seenEls.get(id, {frame: win});
-      resp.body.value = atom.getElementAttribute(el, name, this.getCurrentWindow());
+
+      resp.body.value = el.getAttribute(name);
       break;
 
     case Context.CONTENT: