Layout Tests: Remove assert_will_be_idl_attribute() helper

third_party/WebKit/LayoutTests/http/tests/resources/testharness-helpers.js

 /*
  * testharness-helpers contains various useful extensions to testharness.js to
  * allow them to be used across multiple tests before they have been
  * upstreamed. This file is intended to be usable from both document and worker
  * environments, so code should for example not rely on the DOM.
  */
 
 // Returns a promise that fulfills after the provided |promise| is fulfilled.
 // The |test| succeeds only if |promise| rejects with an exception matching
 // |code|. Accepted values for |code| follow those accepted for assert_throws().
@@ skipping 14 matching lines @@
     function() {
       throw 'assert_promise_rejects: ' + description + ' Promise did not reject.';
     },
     function(e) {
       if (code !== undefined) {
         assert_throws(code, function() { throw e; }, description);
       }
     });
 }
 
-// Asserts that |object| that is an instance of some interface has the attribute
-// |attribute_name| following the conditions specified by WebIDL, but it's
-// acceptable that the attribute |attribute_name| is an own property of the
-// object because we're in the middle of moving the attribute to a prototype
-// chain.  Once we complete the transition to prototype chains,
-// assert_will_be_idl_attribute must be replaced with assert_idl_attribute
-// defined in testharness.js.
-//
-// FIXME: Remove assert_will_be_idl_attribute once we complete the transition
-// of moving the DOM attributes to prototype chains.  (http://crbug.com/43394)
-function assert_will_be_idl_attribute(object, attribute_name, description) {
-  assert_true(typeof object === "object", description);
-
-  assert_true("hasOwnProperty" in object, description);
-
-  // Do not test if |attribute_name| is not an own property because
-  // |attribute_name| is in the middle of the transition to a prototype
-  // chain.  (http://crbug.com/43394)
-
-  assert_true(attribute_name in object, description);
-}
-
 // Stringifies a DOM object.  This function stringifies not only own properties
 // but also DOM attributes which are on a prototype chain.  Note that
 // JSON.stringify only stringifies own properties.
 function stringifyDOMObject(object)
 {
     function deepCopy(src) {
         if (typeof src != "object")
             return src;
         var dst = Array.isArray(src) ? [] : {};
         for (var property in src) {
             dst[property] = deepCopy(src[property]);
         }
         return dst;
     }
     return JSON.stringify(deepCopy(object));
 }