feat(testability): add an initial scaffold for the testability api

Make each application component register itself onto the testability
API and exports the API onto the window object.

modules/angular2/src/dom/browser_adapter.dart

@@ -123,6 +123,7 @@ class BrowserDomAdapter extends GenericBrowserDomAdapter {
   }
   ShadowRoot createShadowRoot(Element el) => el.createShadowRoot();
   ShadowRoot getShadowRoot(Element el) => el.shadowRoot;
+  Element getHost(Element el) => (el as ShadowRoot).host;
   clone(Node node) => node.clone(true);
   bool hasProperty(Element element, String name) =>
       new JsObject.fromBrowserObject(element).hasProperty(name);
@@ -188,6 +189,9 @@ class BrowserDomAdapter extends GenericBrowserDomAdapter {
   bool hasShadowRoot(Node node) {
     return node is Element && node.shadowRoot != null;
   }
+  bool isShadowRoot(Node node) {
+    return node is ShadowRoot;
+  }
   Node importIntoDoc(Node node) {
     return document.importNode(node, true);
   }

modules/angular2/src/dom/browser_adapter.es6

@@ -158,6 +158,9 @@ export class BrowserDomAdapter extends GenericBrowserDomAdapter {
   getShadowRoot(el:HTMLElement): ShadowRoot {
     return el.shadowRoot;
   }
+  getHost(el:HTMLElement): HTMLElement {
+    return el.host;
+  }
   clone(node:Node) {
     return node.cloneNode(true);
   }
@@ -245,6 +248,9 @@ export class BrowserDomAdapter extends GenericBrowserDomAdapter {
   hasShadowRoot(node):boolean {
     return node instanceof HTMLElement && isPresent(node.shadowRoot);
   }
+  isShadowRoot(node):boolean {
+    return node instanceof ShadowRoot;
+  }
   importIntoDoc(node:Node) {
     var result = document.importNode(node, true);
     // Workaround WebKit https://bugs.webkit.org/show_bug.cgi?id=137619

modules/angular2/src/dom/dom_adapter.js

@@ -147,6 +147,9 @@ export class DomAdapter {
   getShadowRoot(el) {
     throw _abstract();
   }
+  getHost(el) {
+    throw _abstract();
+  }
   getDistributedNodes(el) {
     throw _abstract();
   }
@@ -231,6 +234,9 @@ export class DomAdapter {
   hasShadowRoot(node):boolean {
     throw _abstract();
   }
+  isShadowRoot(node):boolean {
+    throw _abstract();
+  }
   importIntoDoc(node) {
     throw _abstract();
   }

modules/angular2/src/dom/html_adapter.dart

@@ -120,6 +120,15 @@ class Html5LibDomAdapter implements DomAdapter {
   createStyleElement(String css, [doc]) {
     throw 'not implemented';
   }
+  createShadowRoot(el) {
+    throw 'not implemented';
+  }
+  getShadowRoot(el) {
+    throw 'not implemented';
+  }
+  getHost(el) {
+    throw 'not implemented';
+  }
   clone(node) {
     throw 'not implemented';
   }
@@ -199,6 +208,9 @@ class Html5LibDomAdapter implements DomAdapter {
   bool hasShadowRoot(node) {
     throw 'not implemented';
   }
+  bool isShadowRoot(node) {
+    throw 'not implemented';
+  }
   importIntoDoc(node) {
     throw 'not implemented';
   }

modules/angular2/src/dom/parse5_adapter.cjs

@@ -252,6 +252,9 @@ export class Parse5DomAdapter extends DomAdapter {
   getShadowRoot(el) {
     return el.shadowRoot;
   }
+  getHost(el) {
+    return el.host;
+  }
   getDistributedNodes(el) {
     throw _notImplemented('getDistributedNodes');
   }
@@ -395,6 +398,9 @@ export class Parse5DomAdapter extends DomAdapter {
   hasShadowRoot(node):boolean {
     return isPresent(node.shadowRoot);
   }
+  isShadowRoot(node): boolean {
+    return this.getShadowRoot(node) == node;
+  }
   importIntoDoc(node) {
     return this.clone(node);
   }