fix: split dynamic bits in platform-browser into platform-browser-dynamic

Previously these symbols were exposed via platform-browser-dynamic, then we merged then into platform-browser
thinking that tools would know how to shake off the compiler and other dynamic bits not used with the offline
compilation flow. This turned out to be wrong as both webpack and rollup don't have good enough tree-shaking
capabilities to do this today. We think that in the future we'll be able to merge these two entry points into
one, but we need to give tooling some time before we can do it. In the meantime the reintroduction of the -dynamic
package point allows us to separate the compiler dependencies from the rest of the framework.

This change undoes the previous breaking change that removed the platform-browser-dynamic package.

modules/@angular/platform-browser-dynamic/src/facade

@@ -0,0 +1 @@
+../../facade/src

modules/@angular/platform-browser-dynamic/src/xhr/xhr_cache.ts

@@ -0,0 +1,31 @@
+import {XHR} from '@angular/compiler';
+import {BaseException} from '../facade/exceptions';
+import {global} from '../facade/lang';
+import {PromiseWrapper} from '../facade/promise';
+
+/**
+ * An implementation of XHR that uses a template cache to avoid doing an actual
+ * XHR.
+ *
+ * The template cache needs to be built and loaded into window.$templateCache
+ * via a separate mechanism.
+ */
+export class CachedXHR extends XHR {
+  private _cache: {[url: string]: string};
+
+  constructor() {
+    super();
+    this._cache = (<any>global).$templateCache;
+    if (this._cache == null) {
+      throw new BaseException('CachedXHR: Template cache was not found in $templateCache.');
+    }
+  }
+
+  get(url: string): Promise<string> {
+    if (this._cache.hasOwnProperty(url)) {
+      return PromiseWrapper.resolve(this._cache[url]);
+    } else {
+      return PromiseWrapper.reject('CachedXHR: Did not find cached template for ' + url, null);
+    }
+  }
+}

modules/@angular/platform-browser-dynamic/src/xhr/xhr_impl.ts

@@ -0,0 +1,40 @@
+import {XHR} from '@angular/compiler';
+
+import {isPresent} from '../facade/lang';
+import {PromiseCompleter, PromiseWrapper} from '../facade/promise';
+
+export class XHRImpl extends XHR {
+  get(url: string): Promise<string> {
+    var completer: PromiseCompleter<string> = PromiseWrapper.completer();
+    var xhr = new XMLHttpRequest();
+    xhr.open('GET', url, true);
+    xhr.responseType = 'text';
+
+    xhr.onload = function() {
+      // responseText is the old-school way of retrieving response (supported by IE8 & 9)
+      // response/responseType properties were introduced in XHR Level2 spec (supported by IE10)
+      var response = isPresent(xhr.response) ? xhr.response : xhr.responseText;
+
+      // normalize IE9 bug (http://bugs.jquery.com/ticket/1450)
+      var status = xhr.status === 1223 ? 204 : xhr.status;
+
+      // fix status code when it is 0 (0 status is undocumented).
+      // Occurs when accessing file resources or on Android 4.1 stock browser
+      // while retrieving files from application cache.
+      if (status === 0) {
+        status = response ? 200 : 0;
+      }
+
+      if (200 <= status && status <= 300) {
+        completer.resolve(response);
+      } else {
+        completer.reject(`Failed to load ${url}`, null);
+      }
+    };
+
+    xhr.onerror = function() { completer.reject(`Failed to load ${url}`, null); };
+
+    xhr.send();
+    return completer.promise;
+  }
+}