refactor(pipes): use angular lifecycle hooks instead of PipeOnDestroy

BREAKING CHANGE:
Previously, pipes that wanted to be notified when they were destroyed
would implement the PipeOnDestroy interface and name the callback
`onDestroy`. This change removes the PipeOnDestroy interface and
instead uses Angular's lifecycle interface `OnDestroy`, with the
`ngOnDestroy` method.

Before:
```
import {Pipe, PipeOnDestroy} from 'angular2/angular2';
@Pipe({pure: false})
export class MyPipe implements PipeOnDestroy {
  onDestroy() {}
}
```

After:
import {Pipe, OnDestroy} from 'angular2/angular2';
@Pipe({pure: false})
export class MyPipe implements PipeOnDestroy {
  ngOnDestroy() {}
}

modules/angular2/test/common/pipes/async_pipe_spec.ts

@@ -96,13 +96,13 @@ export function main() {
            }));
       });
 
-      describe("onDestroy", () => {
+      describe("ngOnDestroy", () => {
         it("should do nothing when no subscription",
-           () => { expect(() => pipe.onDestroy()).not.toThrow(); });
+           () => { expect(() => pipe.ngOnDestroy()).not.toThrow(); });
 
         it("should dispose of the existing subscription", inject([AsyncTestCompleter], (async) => {
              pipe.transform(emitter);
-             pipe.onDestroy();
+             pipe.ngOnDestroy();
 
              ObservableWrapper.callEmit(emitter, message);
 
@@ -182,9 +182,9 @@ export function main() {
              }, timer)
            }));
 
-        describe("onDestroy", () => {
+        describe("ngOnDestroy", () => {
           it("should do nothing when no source",
-             () => { expect(() => pipe.onDestroy()).not.toThrow(); });
+             () => { expect(() => pipe.ngOnDestroy()).not.toThrow(); });
 
           it("should dispose of the existing source", inject([AsyncTestCompleter], (async) => {
                pipe.transform(completer.promise);
@@ -194,7 +194,7 @@ export function main() {
 
                    TimerWrapper.setTimeout(() => {
                      expect(pipe.transform(completer.promise)).toEqual(new WrappedValue(message));
-                     pipe.onDestroy();
+                     pipe.ngOnDestroy();
                      expect(pipe.transform(completer.promise)).toBe(null);
                      async.done();
                    }, timer);

modules/angular2/test/common/pipes/pipes_spec.ts

@@ -10,20 +10,20 @@ import {
   afterEach
 } from 'angular2/testing_internal';
 
-import {Injector, Inject, provide, Pipe, PipeTransform} from 'angular2/core';
+import {Injector, Inject, provide, Pipe, PipeTransform, OnDestroy} from 'angular2/core';
 import {ProtoPipes, Pipes} from 'angular2/src/core/pipes/pipes';
 import {PipeProvider} from 'angular2/src/core/pipes/pipe_provider';
 
-class PipeA implements PipeTransform {
+class PipeA implements PipeTransform, OnDestroy {
   transform(a, b) {}
-  onDestroy() {}
+  ngOnDestroy() {}
 }
 
-class PipeB implements PipeTransform {
+class PipeB implements PipeTransform, OnDestroy {
   dep;
   constructor(@Inject("dep") dep: any) { this.dep = dep; }
   transform(a, b) {}
-  onDestroy() {}
+  ngOnDestroy() {}
 }
 
 export function main() {

modules/angular2/test/core/change_detection/change_detector_spec.ts

@@ -35,7 +35,6 @@ import {
   DirectiveRecord,
   DirectiveIndex,
   PipeTransform,
-  PipeOnDestroy,
   ChangeDetectionStrategy,
   WrappedValue,
   DynamicProtoChangeDetector,
@@ -48,6 +47,7 @@ import {
 
 import {SelectedPipe, Pipes} from 'angular2/src/core/change_detection/pipes';
 import {JitProtoChangeDetector} from 'angular2/src/core/change_detection/jit_proto_change_detector';
+import {OnDestroy} from 'angular2/src/core/linker/interfaces';
 
 import {getDefinition} from './change_detector_config';
 import {createObservableModel} from './change_detector_spec_util';
@@ -1228,7 +1228,7 @@ export function main() {
           expect(cd.hydrated()).toBe(true);
         });
 
-        it('should destroy all active pipes implementing onDestroy during dehyration', () => {
+        it('should destroy all active pipes implementing ngOnDestroy during dehyration', () => {
           var pipe = new PipeWithOnDestroy();
           var registry = new FakePipes('pipe', () => pipe);
           var cd = _createChangeDetector('name | pipe', new Person('bob'), registry).changeDetector;
@@ -1239,7 +1239,7 @@ export function main() {
           expect(pipe.destroyCalled).toBe(true);
         });
 
-        it('should not call onDestroy all pipes that do not implement onDestroy', () => {
+        it('should not call ngOnDestroy all pipes that do not implement ngOnDestroy', () => {
           var pipe = new CountingPipe();
           var registry = new FakePipes('pipe', () => pipe);
           var cd = _createChangeDetector('name | pipe', new Person('bob'), registry).changeDetector;
@@ -1365,9 +1365,9 @@ class CountingPipe implements PipeTransform {
   transform(value, args = null) { return `${value} state:${this.state ++}`; }
 }
 
-class PipeWithOnDestroy implements PipeTransform, PipeOnDestroy {
+class PipeWithOnDestroy implements PipeTransform, OnDestroy {
   destroyCalled: boolean = false;
-  onDestroy() { this.destroyCalled = true; }
+  ngOnDestroy() { this.destroyCalled = true; }
 
   transform(value, args = null) { return null; }
 }

modules/angular2/test/core/linker/integration_spec.ts

@@ -54,7 +54,8 @@ import {
   Inject,
   Host,
   SkipSelf,
-  SkipSelfMetadata
+  SkipSelfMetadata,
+  OnDestroy
 } from 'angular2/core';
 
 import {NgIf, NgFor} from 'angular2/common';
@@ -1999,8 +2000,8 @@ class SomeViewport {
 }
 
 @Pipe({name: 'double'})
-class DoublePipe implements PipeTransform {
-  onDestroy() {}
+class DoublePipe implements PipeTransform, OnDestroy {
+  ngOnDestroy() {}
   transform(value, args = null) { return `${value}${value}`; }
 }
 

modules/angular2/test/public_api_spec.ts

@@ -108,7 +108,7 @@ var NG_ALL = [
   'ApplicationRef.tick()',
   */
   'AsyncPipe',
-  'AsyncPipe.onDestroy()',
+  'AsyncPipe.ngOnDestroy()',
   'AsyncPipe.transform()',
   'Attribute',
   'Attribute.attributeName',
@@ -1425,7 +1425,6 @@ var NG_ALL = [
   'OnChanges:dart',
   'OnDestroy:dart',
   'OnInit:dart',
-  'PipeOnDestroy:dart',
   'PipeTransform:dart',
   'reflector',
   'RenderBeginCmd:dart',