feat(core): introduce ModuleWithProviders.

Modules can now provider helper functions that allow
to import a module together with an array of providers.

Part of #10043

modules/@angular/core/src/metadata.ts

@@ -16,13 +16,13 @@ import {ChangeDetectionStrategy} from '../src/change_detection/change_detection'
 import {AnimationEntryMetadata} from './animation/metadata';
 import {AttributeMetadata, ContentChildMetadata, ContentChildrenMetadata, QueryMetadata, ViewChildMetadata, ViewChildrenMetadata, ViewQueryMetadata} from './metadata/di';
 import {ComponentMetadata, DirectiveMetadata, HostBindingMetadata, HostListenerMetadata, InputMetadata, OutputMetadata, PipeMetadata} from './metadata/directives';
-import {NgModuleMetadata} from './metadata/ng_module';
+import {ModuleWithProviders, NgModuleMetadata} from './metadata/ng_module';
 import {ViewEncapsulation, ViewMetadata} from './metadata/view';
 
 export {ANALYZE_FOR_ENTRY_COMPONENTS, AttributeMetadata, ContentChildMetadata, ContentChildrenMetadata, QueryMetadata, ViewChildMetadata, ViewChildrenMetadata, ViewQueryMetadata} from './metadata/di';
 export {ComponentMetadata, DirectiveMetadata, HostBindingMetadata, HostListenerMetadata, InputMetadata, OutputMetadata, PipeMetadata} from './metadata/directives';
 export {AfterContentChecked, AfterContentInit, AfterViewChecked, AfterViewInit, DoCheck, OnChanges, OnDestroy, OnInit} from './metadata/lifecycle_hooks';
-export {NgModuleMetadata} from './metadata/ng_module';
+export {ModuleWithProviders, NgModuleMetadata} from './metadata/ng_module';
 export {ViewEncapsulation, ViewMetadata} from './metadata/view';
 
 import {makeDecorator, makeParamDecorator, makePropDecorator, TypeDecorator,} from './util/decorators';
@@ -498,7 +498,7 @@ export interface NgModuleMetadataFactory {
   (obj?: {
     providers?: any[],
     declarations?: Array<Type|any[]>,
-    imports?: Array<Type|any[]>,
+    imports?: Array<Type|ModuleWithProviders|any[]>,
     exports?: Array<Type|any[]>,
     entryComponents?: Array<Type|any[]>
   }): NgModuleDecorator;

modules/@angular/core/src/metadata/ng_module.ts

@@ -9,6 +9,16 @@
 import {InjectableMetadata} from '../di/metadata';
 import {Type} from '../facade/lang';
 
+/**
+ * A wrapper around a module that also includes the providers.
+ *
+ * @experimental
+ */
+export interface ModuleWithProviders {
+  ngModule: Type;
+  providers?: any[];
+}
+
 /**
  * Declares an Angular Module.
  * @experimental
@@ -65,6 +75,7 @@ export class NgModuleMetadata extends InjectableMetadata {
   /**
    * Specifies a list of modules whose exported directives/pipes
    * should be available to templates in this module.
+   * This can also contain {@link ModuleWithProviders}.
    *
    * ### Example
    *
@@ -76,7 +87,7 @@ export class NgModuleMetadata extends InjectableMetadata {
    * }
    * ```
    */
-  imports: Array<Type|any[]>;
+  imports: Array<Type|ModuleWithProviders|any[]>;
 
   /**
    * Specifies a list of directives/pipes/module that can be used within the template