refactor(xhr): move render's xhr implementation to render/

The existence of this module in the services/ folder led some to believe xhr
is meant to be a general-purpose http library.

Fixes #2305

modules/angular2/src/mock/xhr_mock.ts

@@ -1,105 +0,0 @@
-import {XHR} from 'angular2/src/services/xhr';
-import {List, ListWrapper, Map, MapWrapper} from 'angular2/src/facade/collection';
-import {isBlank, isPresent, normalizeBlank, BaseException} from 'angular2/src/facade/lang';
-import {PromiseWrapper, Promise} from 'angular2/src/facade/async';
-
-export class MockXHR extends XHR {
-  private _expectations: List<_Expectation>;
-  private _definitions: Map<string, string>;
-  private _requests: List<Promise<string>>;
-
-  constructor() {
-    super();
-    this._expectations = [];
-    this._definitions = MapWrapper.create();
-    this._requests = [];
-  }
-
-  get(url: string): Promise<string> {
-    var request = new _PendingRequest(url);
-    ListWrapper.push(this._requests, request);
-    return request.getPromise();
-  }
-
-  expect(url: string, response: string) {
-    var expectation = new _Expectation(url, response);
-    ListWrapper.push(this._expectations, expectation);
-  }
-
-  when(url: string, response: string) { MapWrapper.set(this._definitions, url, response); }
-
-  flush() {
-    if (this._requests.length === 0) {
-      throw new BaseException('No pending requests to flush');
-    }
-
-    do {
-      var request = ListWrapper.removeAt(this._requests, 0);
-      this._processRequest(request);
-    } while (this._requests.length > 0);
-
-    this.verifyNoOustandingExpectations();
-  }
-
-  verifyNoOustandingExpectations() {
-    if (this._expectations.length === 0) return;
-
-    var urls = [];
-    for (var i = 0; i < this._expectations.length; i++) {
-      var expectation = this._expectations[i];
-      ListWrapper.push(urls, expectation.url);
-    }
-
-    throw new BaseException(`Unsatisfied requests: ${ListWrapper.join(urls, ', ')}`);
-  }
-
-  private _processRequest(request: _PendingRequest) {
-    var url = request.url;
-
-    if (this._expectations.length > 0) {
-      var expectation = this._expectations[0];
-      if (expectation.url == url) {
-        ListWrapper.remove(this._expectations, expectation);
-        request.complete(expectation.response);
-        return;
-      }
-    }
-
-    if (MapWrapper.contains(this._definitions, url)) {
-      var response = MapWrapper.get(this._definitions, url);
-      request.complete(normalizeBlank(response));
-      return;
-    }
-
-    throw new BaseException(`Unexpected request ${url}`);
-  }
-}
-
-class _PendingRequest {
-  url: string;
-  completer;
-
-  constructor(url) {
-    this.url = url;
-    this.completer = PromiseWrapper.completer();
-  }
-
-  complete(response: string) {
-    if (isBlank(response)) {
-      this.completer.reject(`Failed to load ${this.url}`, null);
-    } else {
-      this.completer.resolve(response);
-    }
-  }
-
-  getPromise(): Promise<string> { return this.completer.promise; }
-}
-
-class _Expectation {
-  url: string;
-  response: string;
-  constructor(url: string, response: string) {
-    this.url = url;
-    this.response = response;
-  }
-}