feat(core): expose inputs, outputs and ngContentSelectors on ComponentFactory. (#15214)

E.g. for a component like this:
```
@Component({
  template: ‘<ng-content select=“child”></ng-content>’
})
class MyComp {
  @Input(‘aInputName’)
  aInputProp: string;

  @Output(‘aEventName’)
  aOuputProp: EventEmitter<any>;
}
```

the `ComponentFactory` will now contain the following:
- `inputs = {aInputProp: ‘aInputName’}`
- `outputs = {aOutputProp: ‘aOutputName’}`
- `ngContentSelectors = [‘child’]`

packages/core/src/linker/compiler.ts

@@ -73,6 +73,8 @@ export class Compiler {
    * the template of the given component.
    * This is used by the `upgrade` library to compile the appropriate transclude content
    * in the AngularJS wrapper component.
+   *
+   * @deprecated since v4. Use ComponentFactory.ngContentSelectors instead.
    */
   getNgContentSelectors(component: Type<any>): string[] { throw _throwError(); }
 

packages/core/src/linker/component_factory.ts

@@ -70,6 +70,18 @@ export abstract class ComponentRef<C> {
 export abstract class ComponentFactory<C> {
   abstract get selector(): string;
   abstract get componentType(): Type<any>;
+  /**
+   * selector for all <ng-content> elements in the component.
+   */
+  abstract get ngContentSelectors(): string[];
+  /**
+   * the inputs of the component.
+   */
+  abstract get inputs(): {propName: string, templateName: string}[];
+  /**
+   * the outputs of the component.
+   */
+  abstract get outputs(): {propName: string, templateName: string}[];
   /**
    * Creates a new component.
    */

packages/core/src/linker/component_factory_resolver.ts

@@ -65,6 +65,9 @@ export class ComponentFactoryBoundToModule<C> extends ComponentFactory<C> {
 
   get selector() { return this.factory.selector; }
   get componentType() { return this.factory.componentType; }
+  get ngContentSelectors() { return this.factory.ngContentSelectors; }
+  get inputs() { return this.factory.inputs; }
+  get outputs() { return this.factory.outputs; }
 
   create(
       injector: Injector, projectableNodes?: any[][], rootSelectorOrNode?: string|any,