feat(core): map 'for' attribute to 'htmlFor' property (#10546)

This improves ergonomics a bit by allowing people to write:
`<label [for]="ctxProp"></label>`.
This is similar to the existing class -> className mapping.

Closes #7516

Author: pkozlowski-opensource

modules/@angular/compiler/src/schema/dom_element_schema_registry.ts

@@ -231,6 +231,7 @@ const SCHEMA:
 
 const _ATTR_TO_PROP: {[name: string]: string} = {
   'class': 'className',
+  'for': 'htmlFor',
   'formaction': 'formAction',
   'innerHtml': 'innerHTML',
   'readonly': 'readOnly',

modules/@angular/core/test/linker/integration_spec.ts

@@ -217,6 +217,19 @@ function declareTests({useJit}: {useJit: boolean}) {
         expect(nativeEl).not.toHaveCssClass('initial');
       });
 
+      it('should consume binding to htmlFor using for alias', () => {
+        const template = '<label [for]="ctxProp"></label>';
+        const fixture = TestBed.configureTestingModule({declarations: [MyComp]})
+                            .overrideComponent(MyComp, {set: {template}})
+                            .createComponent(MyComp);
+
+        const nativeEl = fixture.debugElement.children[0].nativeElement;
+        fixture.debugElement.componentInstance.ctxProp = 'foo';
+        fixture.detectChanges();
+
+        expect(nativeEl.htmlFor).toBe('foo');
+      });
+
       it('should consume directive watch expression change.', () => {
         TestBed.configureTestingModule({declarations: [MyComp, MyDir]});
         const template = '<span>' +