Remove proxying support from dart:html

tests/html/js_interop_obj_passing_test.dart

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file
-
-#library('JsInteropObjPassingTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
-#import('dart:isolate');
-
-injectSource(code) {
-  final script = new ScriptElement();
-  script.type = 'text/javascript';
-  script.innerHTML = code;
-  document.body.nodes.add(script);
-}
-
-var jsProxyTest = """
-  function TestType(x) {
-    this.x = x;
-  }
-  TestType.prototype.razzle = function () {
-    return this.x * 2;
-  }
-  var data = new TestType(21);
-
-  var port1 = new ReceivePortSync();
-  port1.receive(function (x) {
-    return x.razzle();
-  });
-  window.registerPort('test1a', port1.toSendPort());
-
-  var port2 = window.lookupPort('test1b');
-  port2.callSync(data);
-""";
-
-var dartProxyTest = """
-  var port2 = new ReceivePortSync();
-  port2.receive(function (x) {
-    var port1 = window.lookupPort('test2a');
-    port1.callSync(x);
-  });
-  window.registerPort('test2b', port2.toSendPort());
-""";
-
-main() {
-  useHtmlConfiguration();
-
-  test('js-proxy', () {
-    int invoked = 0;
-
-    var port2 = new ReceivePortSync();
-    port2.receive((x) {
-      var port1 = window.lookupPort('test1a');
-      var result = port1.callSync(x);
-      expect(result, equals(42));
-      ++invoked;
-    });
-    window.registerPort('test1b', port2.toSendPort());
-
-    injectSource(jsProxyTest);
-    expect(invoked, equals(1));
-  });
-
-  test('dart-proxy', () {
-    injectSource(dartProxyTest);
-
-    var buffer = new StringBuffer();
-    buffer.add('hello');
-
-    var port1 = new ReceivePortSync();
-    port1.receive((x) => x.add(' from dart'));
-    window.registerPort('test2a', port1.toSendPort());
-
-    var port2 = window.lookupPort('test2b');
-    port2.callSync(buffer);
-
-    expect(buffer.toString(), equals('hello from dart'));
-  });
-}