refactor(common): remove some facade usages

modules/@angular/common/src/directives/ng_class.ts

@@ -9,7 +9,7 @@
 import {Directive, DoCheck, ElementRef, Input, IterableChanges, IterableDiffer, IterableDiffers, KeyValueChanges, KeyValueDiffer, KeyValueDiffers, Renderer} from '@angular/core';
 
 import {isListLikeIterable} from '../facade/collection';
-import {isPresent, stringify} from '../facade/lang';
+import {stringify} from '../facade/lang';
 
 /**
  * @ngModule CommonModule
@@ -129,7 +129,7 @@ export class NgClass implements DoCheck {
         (<any>rawClassVal).forEach((klass: string) => this._toggleClass(klass, !isCleanup));
       } else {
         Object.keys(rawClassVal).forEach(klass => {
-          if (isPresent(rawClassVal[klass])) this._toggleClass(klass, !isCleanup);
+          if (rawClassVal[klass] != null) this._toggleClass(klass, !isCleanup);
         });
       }
     }

modules/@angular/common/src/pipes/i18n_plural_pipe.ts

@@ -7,7 +7,6 @@
  */
 
 import {Pipe, PipeTransform} from '@angular/core';
-import {isBlank} from '../facade/lang';
 import {NgLocalization, getPluralCategory} from '../localization';
 import {InvalidPipeArgumentError} from './invalid_pipe_argument_error';
 
@@ -35,7 +34,7 @@ export class I18nPluralPipe implements PipeTransform {
   constructor(private _localization: NgLocalization) {}
 
   transform(value: number, pluralMap: {[count: string]: string}): string {
-    if (isBlank(value)) return '';
+    if (value == null) return '';
 
     if (typeof pluralMap !== 'object' || pluralMap === null) {
       throw new InvalidPipeArgumentError(I18nPluralPipe, pluralMap);

modules/@angular/common/src/pipes/number_pipe.ts

@@ -8,7 +8,7 @@
 
 import {Inject, LOCALE_ID, Pipe, PipeTransform, Type} from '@angular/core';
 
-import {NumberWrapper, isBlank, isPresent} from '../facade/lang';
+import {NumberWrapper} from '../facade/lang';
 
 import {NumberFormatStyle, NumberFormatter} from './intl';
 import {InvalidPipeArgumentError} from './invalid_pipe_argument_error';
@@ -18,7 +18,7 @@ const _NUMBER_FORMAT_REGEXP = /^(\d+)?\.((\d+)(-(\d+))?)?$/;
 function formatNumber(
     pipe: Type<any>, locale: string, value: number | string, style: NumberFormatStyle,
     digits: string, currency: string = null, currencyAsSymbol: boolean = false): string {
-  if (isBlank(value)) return null;
+  if (value == null) return null;
 
   // Convert strings to numbers
   value = typeof value === 'string' && NumberWrapper.isNumeric(value) ? +value : value;
@@ -41,13 +41,13 @@ function formatNumber(
     if (parts === null) {
       throw new Error(`${digits} is not a valid digit info for number pipes`);
     }
-    if (isPresent(parts[1])) {  // min integer digits
+    if (parts[1] != null) {  // min integer digits
       minInt = NumberWrapper.parseIntAutoRadix(parts[1]);
     }
-    if (isPresent(parts[3])) {  // min fraction digits
+    if (parts[3] != null) {  // min fraction digits
       minFraction = NumberWrapper.parseIntAutoRadix(parts[3]);
     }
-    if (isPresent(parts[5])) {  // max fraction digits
+    if (parts[5] != null) {  // max fraction digits
       maxFraction = NumberWrapper.parseIntAutoRadix(parts[5]);
     }
   }

modules/@angular/common/src/pipes/slice_pipe.ts

@@ -7,7 +7,6 @@
  */
 
 import {Pipe, PipeTransform} from '@angular/core';
-import {isBlank} from '../facade/lang';
 import {InvalidPipeArgumentError} from './invalid_pipe_argument_error';
 
 /**
@@ -58,7 +57,7 @@ import {InvalidPipeArgumentError} from './invalid_pipe_argument_error';
 @Pipe({name: 'slice', pure: false})
 export class SlicePipe implements PipeTransform {
   transform(value: any, start: number, end?: number): any {
-    if (isBlank(value)) return value;
+    if (value == null) return value;
 
     if (!this.supports(value)) {
       throw new InvalidPipeArgumentError(SlicePipe, value);