feat(change_detect): Guard checkNoChanges behind assertionsEnabled

Always generate `checkNoChanges` tests, but guard them behind
`assertionsEnabled` tests.

Closes #4560

modules/angular2/src/core/change_detection/abstract_change_detector.ts

@@ -1,5 +1,4 @@
-import {isPresent, isBlank, StringWrapper} from 'angular2/src/core/facade/lang';
-import {BaseException} from 'angular2/src/core/facade/exceptions';
+import {assertionsEnabled, isPresent, isBlank, StringWrapper} from 'angular2/src/core/facade/lang';
 import {ListWrapper} from 'angular2/src/core/facade/collection';
 import {ChangeDetectionUtil} from './change_detection_util';
 import {ChangeDetectorRef, ChangeDetectorRef_} from './change_detector_ref';
@@ -76,7 +75,11 @@ export class AbstractChangeDetector<T> implements ChangeDetector {
 
   detectChanges(): void { this.runDetectChanges(false); }
 
-  checkNoChanges(): void { throw new BaseException("Not implemented"); }
+  checkNoChanges(): void {
+    if (assertionsEnabled()) {
+      this.runDetectChanges(true);
+    }
+  }
 
   runDetectChanges(throwOnChange: boolean): void {
     if (this.mode === ChangeDetectionStrategy.Detached ||

modules/angular2/src/core/change_detection/change_detection_jit_generator.ts

@@ -1,4 +1,10 @@
-import {Type, isBlank, isPresent, StringWrapper} from 'angular2/src/core/facade/lang';
+import {
+  Type,
+  assertionsEnabled,
+  isBlank,
+  isPresent,
+  StringWrapper
+} from 'angular2/src/core/facade/lang';
 import {BaseException} from 'angular2/src/core/facade/exceptions';
 import {ListWrapper, MapWrapper, StringMapWrapper} from 'angular2/src/core/facade/collection';
 
@@ -97,8 +103,6 @@ export class ChangeDetectorJITGenerator {
 
       ${this._maybeGenHandleEventInternal()}
 
-      ${this._genCheckNoChanges()}
-
       ${this._maybeGenAfterContentLifecycleCallbacks()}
 
       ${this._maybeGenAfterViewLifecycleCallbacks()}
@@ -434,7 +438,7 @@ export class ChangeDetectorJITGenerator {
 
   /** @internal */
   _genThrowOnChangeCheck(oldValue: string, newValue: string): string {
-    if (this.genConfig.genCheckNoChanges) {
+    if (assertionsEnabled()) {
       return `
         if(throwOnChange) {
           this.throwOnChangeError(${oldValue}, ${newValue});
@@ -445,15 +449,6 @@ export class ChangeDetectorJITGenerator {
     }
   }
 
-  /** @internal */
-  _genCheckNoChanges(): string {
-    if (this.genConfig.genCheckNoChanges) {
-      return `${this.typeName}.prototype.checkNoChanges = function() { this.runDetectChanges(true); }`;
-    } else {
-      return '';
-    }
-  }
-
   /** @internal */
   _genAddToChanges(r: ProtoRecord): string {
     var newValue = this._names.getLocalName(r.selfIndex);

modules/angular2/src/core/change_detection/interfaces.ts

@@ -39,8 +39,8 @@ export interface ChangeDetector {
 export interface ProtoChangeDetector { instantiate(dispatcher: ChangeDispatcher): ChangeDetector; }
 
 export class ChangeDetectorGenConfig {
-  constructor(public genCheckNoChanges: boolean, public genDebugInfo: boolean,
-              public logBindingUpdate: boolean, public useJit: boolean) {}
+  constructor(public genDebugInfo: boolean, public logBindingUpdate: boolean,
+              public useJit: boolean) {}
 }
 
 export class ChangeDetectorDefinition {

modules/angular2/src/core/change_detection/pregen_proto_change_detector.dart

@@ -19,7 +19,7 @@ export 'package:angular2/src/core/change_detection/proto_record.dart'
     show ProtoRecord;
 export 'package:angular2/src/core/change_detection/change_detection_util.dart'
     show ChangeDetectionUtil;
-export 'package:angular2/src/core/facade/lang.dart' show looseIdentical;
+export 'package:angular2/src/core/facade/lang.dart' show assertionsEnabled, looseIdentical;
 
 typedef ProtoChangeDetector PregenProtoChangeDetectorFactory(
     ChangeDetectorDefinition definition);