Skip 'accessibilityController' property in the cached properties test

https://codereview.chromium.org/172263002/ moves AccessibilityController
from CppBoundClass to gin::Wrappable, and that CL changes this cached-
properties test's result so that 'accessibilityController' is enumerated
as properties of an object. However, it is hard to expect a stable cache
result of WebAXObject of AccessibilityController for now.

BUG=297480, 331301, 347331

Review URL: https://codereview.chromium.org/184233004

git-svn-id: svn://svn.chromium.org/blink/trunk@168564 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/fast/dom/Window/resources/window-property-collector.js

@@ -62,7 +62,13 @@ function collectPropertiesHelper(object, path)
 {
     if (path.length > 20)
         throw 'Error: probably looping';
+
     for (var property in object) {
+        // Skip the properties which are hard to expect a stable result.
+        // As for 'accessibilityController', we can hardly estimate the states
+        // of the cached WebAXObjects.
+        if (property == 'accessibilityController')
+            continue;
         if (!object[property])
             continue;
         path.push(property);
@@ -85,4 +91,3 @@ function collectPropertiesHelper(object, path)
         path.pop();
     }
 }
-