refactor(core): Move LifeCycle functionality into ApplicationRef.

BREAKING CHANGE:

Before: constructor(@Inject(LifeCycle) lifecycle) { lifecycle.tick(); }
After: constructor(@Inject(ApplicationRef) appRef) { appRef.tick(); }

Closes #5008

modules/angular2/test/tools/spies.dart

@@ -1,11 +1,13 @@
 import 'package:angular2/testing_internal.dart' show SpyObject;
-import 'package:angular2/core.dart' show LifeCycle, Injector, bind;
+import 'package:angular2/core.dart' show Injector, bind;
+import 'package:angular2/src/core/application_ref.dart' show ApplicationRef;
 import 'package:angular2/src/core/linker/dynamic_component_loader.dart'
     show ComponentRef_;
 import 'dart:js';
 
 @proxy
-class SpyLifeCycle extends SpyObject implements LifeCycle {
+class SpyApplicationRef extends SpyObject implements ApplicationRef {
+  tick() {}
   noSuchMethod(m) => super.noSuchMethod(m);
 }
 
@@ -15,7 +17,7 @@ class SpyComponentRef extends SpyObject implements ComponentRef_ {
 
   SpyComponentRef() {
     this.injector =
-        Injector.resolveAndCreate([bind(LifeCycle).toClass(SpyLifeCycle)]);
+        Injector.resolveAndCreate([bind(ApplicationRef).toClass(SpyApplicationRef)]);
   }
 
   noSuchMethod(m) => super.noSuchMethod(m);

modules/angular2/test/tools/spies.ts

@@ -1,13 +1,19 @@
 import {SpyObject} from 'angular2/testing_internal';
-import {LifeCycle, Injector, provide} from 'angular2/angular2';
+import {Injector, provide} from 'angular2/angular2';
 import {ComponentRef} from 'angular2/src/core/linker/dynamic_component_loader';
 import {global} from 'angular2/src/core/facade/lang';
+import {ApplicationRef, ApplicationRef_} from 'angular2/src/core/application_ref';
+
+export class SpyApplicationRef extends SpyObject {
+  constructor() { super(ApplicationRef_); }
+}
 
 export class SpyComponentRef extends SpyObject {
   injector;
   constructor() {
     super();
-    this.injector = Injector.resolveAndCreate([provide(LifeCycle, {useValue: {tick: () => {}}})]);
+    this.injector =
+        Injector.resolveAndCreate([provide(ApplicationRef, {useClass: SpyApplicationRef})]);
   }
 }