chore: update pubspec.lock
Revert "chore: update pubspec.lock"

This reverts commit 1eebe45b492dcf2fcab4dfc18fe9207a5aa65177.

Travis fails: https://travis-ci.org/angular/angular.dart/builds/31741920
chore(test): disable failing E2E tests

Work around issue #1316.  Two E2E tests have begun to fail for unknown
reasons.  Disabling them until they're fixed properly.

Closes #1317
chore(style): cleanup to match g3v1x
chore(view_factory): register cache as ViewCache
fix(web_platform): include selector in viewFactoryCache key
chore(introspection): delete introspection_js.dart

This was incorrectly resurrected.
feat(components): implement css encapsulation for transcluding components

* Extract ComponentCssLoader so it can be shared by ShadowDomComponentFactory and TranscludingComponentFactory
* Implement a CSS transformer similar to the one provided by Platform.JS
* Rename EventHandler into ShadowBoundary
* Provide a built-in implementation of WebPlatformShim

Closes #1300