refactor(upgrade): remove imports from angular2/angular2

Related #5739

modules/angular2/src/upgrade/downgrade_ng2_adapter.ts

@@ -1,5 +1,4 @@
 import {
-  bind,
   provide,
   AppViewManager,
   ChangeDetectorRef,
@@ -8,7 +7,7 @@ import {
   OnChanges,
   ProtoViewRef,
   SimpleChange
-} from 'angular2/angular2';
+} from 'angular2/core';
 import {NG1_SCOPE} from './constants';
 import {ComponentInfo} from './metadata';
 import Element = protractor.Element;

modules/angular2/src/upgrade/metadata.ts

@@ -1,4 +1,4 @@
-import {Type, ComponentMetadata, DirectiveResolver, DirectiveMetadata} from 'angular2/angular2';
+import {Type, DirectiveResolver, DirectiveMetadata} from 'angular2/core';
 import {stringify} from './util';
 
 var COMPONENT_SELECTOR = /^[\w|-]*$/;

modules/angular2/src/upgrade/upgrade_adapter.ts

@@ -1,20 +1,17 @@
 import {
-  bind,
   provide,
   platform,
   ApplicationRef,
   AppViewManager,
   Compiler,
-  Inject,
   Injector,
   NgZone,
   PlatformRef,
   ProtoViewRef,
   Provider,
-  Type
+  Type,
-} from 'angular2/angular2';
+  APPLICATION_COMMON_PROVIDERS
-import {APPLICATION_COMMON_PROVIDERS} from 'angular2/core';
+} from 'angular2/core';
-import {COMPILER_PROVIDERS} from 'angular2/src/compiler/compiler';
 import {ObservableWrapper} from 'angular2/src/facade/async';
 import {BROWSER_PROVIDERS, BROWSER_APP_PROVIDERS} from 'angular2/platform/browser';
 

modules/angular2/src/upgrade/upgrade_ng1_adapter.ts

@@ -7,7 +7,7 @@ import {
   OnChanges,
   SimpleChange,
   Type
-} from 'angular2/angular2';
+} from 'angular2/core';
 import {
   NG1_COMPILE,
   NG1_SCOPE,