feat(forms/validators): pattern validator

Adding static pattern validation method to Validators

Adding a directive for the pattern validator

Applying clang-format rules to modified files

Updating public api spec for new pattern validator

Adding pattern validator to public api guard tool

For #5411

Closes #5561

modules/angular2/test/common/forms/validators_spec.ts

@@ -66,12 +66,28 @@ export function main() {
       it("should not error on valid strings",
          () => { expect(Validators.maxLength(2)(new Control("aa"))).toEqual(null); });
 
-      it("should error on short strings", () => {
+      it("should error on long strings", () => {
         expect(Validators.maxLength(2)(new Control("aaa")))
             .toEqual({"maxlength": {"requiredLength": 2, "actualLength": 3}});
       });
     });
 
+    describe("pattern", () => {
+      it("should not error on an empty string",
+         () => { expect(Validators.pattern("[a-zA-Z ]*")(new Control(""))).toEqual(null); });
+
+      it("should not error on null",
+         () => { expect(Validators.pattern("[a-zA-Z ]*")(new Control(null))).toEqual(null); });
+
+      it("should not error on valid strings",
+         () => { expect(Validators.pattern("[a-zA-Z ]*")(new Control("aaAA"))).toEqual(null); });
+
+      it("should error on failure to match string", () => {
+        expect(Validators.pattern("[a-zA-Z ]*")(new Control("aaa0")))
+            .toEqual({"pattern": {"requiredPattern": "^[a-zA-Z ]*$", "actualValue": "aaa0"}});
+      });
+    });
+
     describe("compose", () => {
       it("should return null when given null",
          () => { expect(Validators.compose(null)).toBe(null); });

modules/angular2/test/public_api_spec.ts

@@ -427,6 +427,8 @@ var NG_COMMON = [
   'ObservableListDiffFactory.create():dart',
   'ObservableListDiffFactory.supports():dart',
   'ObservableListDiffFactory:dart',
+  'PatternValidator',
+  'PatternValidator.validate()',
   'PercentPipe',
   'PercentPipe.transform()',
   'RequiredValidator',
@@ -452,6 +454,7 @@ var NG_COMMON = [
   'Validators#maxLength()',
   'Validators#minLength()',
   'Validators#nullValidator()',
+  'Validators#pattern()',
   'Validators#required()',
   'RadioButtonState',
   'RadioButtonState.checked',