feat(compiler, ShadowDom): adds TemplateLoader using XHR.

Also adds css shimming for emulated shadow dom and makes the shadowDom
strategy global to the application.

modules/angular2/src/mock/xhr_mock.js

@@ -0,0 +1,108 @@
+import {XHR} from 'angular2/src/core/compiler/xhr/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 XHRMock extends XHR {
+  _expectations: List<_Expectation>;
+  _definitions: Map;
+  _requests: List<Promise>;
+
+  constructor() {
+    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, ', ')}`);
+  }
+
+  _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}`);
+    } else {
+      this.completer.complete(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;
+  }
+}