feat(forms): add the submitted flag to NgForm and NgFormModel directives

Closes #2960

Closes #7449

modules/@angular/common/src/forms/directives/ng_form.ts

@@ -86,6 +86,8 @@ export const formDirectiveProvider: any =
   exportAs: 'ngForm'
 })
 export class NgForm extends ControlContainer implements Form {
+  private _submitted: boolean = false;
+
   form: ControlGroup;
   ngSubmit = new EventEmitter();
 
@@ -96,6 +98,8 @@ export class NgForm extends ControlContainer implements Form {
                                  composeAsyncValidators(asyncValidators));
   }
 
+  get submitted(): boolean { return this._submitted; }
+
   get formDirective(): Form { return this; }
 
   get control(): ControlGroup { return this.form; }
@@ -158,6 +162,7 @@ export class NgForm extends ControlContainer implements Form {
   }
 
   onSubmit(): boolean {
+    this._submitted = true;
     ObservableWrapper.callEmit(this.ngSubmit, null);
     return false;
   }

modules/@angular/common/src/forms/directives/ng_form_model.ts

@@ -107,6 +107,8 @@ export const formDirectiveProvider: any =
 })
 export class NgFormModel extends ControlContainer implements Form,
     OnChanges {
+  private _submitted: boolean = false;
+
   form: ControlGroup = null;
   directives: NgControl[] = [];
   ngSubmit = new EventEmitter();
@@ -131,6 +133,8 @@ export class NgFormModel extends ControlContainer implements Form,
     this._updateDomValue();
   }
 
+  get submitted(): boolean { return this._submitted; }
+
   get formDirective(): Form { return this; }
 
   get control(): ControlGroup { return this.form; }
@@ -166,6 +170,7 @@ export class NgFormModel extends ControlContainer implements Form,
   }
 
   onSubmit(): boolean {
+    this._submitted = true;
     ObservableWrapper.callEmit(this.ngSubmit, null);
     return false;
   }