title: DatePipe is not working correctly in Angular 6
body: <p>In my Angular application after upgrading from version 5 to 6, this error is occurring when using DatePipe.</p>
  
  <p>I'm saving a Date () object that the <a href="https://material.angular.io/components/datepicker/overview" rel="noreferrer">mat-date-picker</a> creates in the Cloud Firestore with the name of the date_field, when returned try to show on screen to the user but does not appear.</p>
  
  <p>I checked the database and it is saving correctly, but I can not display it on the screen for the user in the child_name field.</p>
  
  <p>When you try to display the date_field column in <a href="https://material.angular.io/components/table/overview" rel="noreferrer">mat-table</a> and use DatePipe to format the date error is occurring.</p>
  
  <p>Below is the HTML code:</p>
  
  <pre><code>&lt;ng-container cdkColumnDef="data_nascimento"&gt;
     &lt;mat-header-cell *cdkHeaderCellDef mat-sort-header fxHide fxShow.gt-xs&gt;Data de nascimento&lt;/mat-header-cell&gt;
     &lt;mat-cell *cdkCellDef="let paciente" fxHide fxShow.gt-xs&gt;
        &lt;p class="text-truncate"&gt;{{paciente.data_nascimento | date}}&lt;/p&gt;
     &lt;/mat-cell&gt;
  &lt;/ng-container&gt;
  </code></pre>
  
  <p>After upgrading to Angular 6 the following error occurs:</p>
  
  <pre><code>ERROR Error: InvalidPipeArgument: 'Unable to convert "Timestamp(seconds=1531364400, nanoseconds=0)" into a date' for pipe 'DatePipe'
      at invalidPipeArgumentError (common.js:4238)
      at DatePipe.push../node_modules/@angular/common/fesm5/common.js.DatePipe.transform (common.js:5151)
      at checkAndUpdatePureExpressionInline (core.js:10801)
      at checkAndUpdateNodeInline (core.js:11375)
      at checkAndUpdateNode (core.js:11333)
      at debugCheckAndUpdateNode (core.js:11970)
      at debugCheckRenderNodeFn (core.js:11956)
      at Object.eval [as updateRenderer] (PacientesComponent.html:81)
      at Object.debugUpdateRenderer [as updateRenderer] (core.js:11948)
      at checkAndUpdateView (core.js:11320)
  View_PacientesComponent_10 @ PacientesComponent.html:81
  push../node_modules/@angular/core/fesm5/core.js.DebugContext_.logError @ core.js:12174
  push../node_modules/@angular/core/fesm5/core.js.ErrorHandler.handleError @ core.js:1650
  (anonymous) @ core.js:5102
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:388
  push../node_modules/zone.js/dist/zone.js.Zone.run @ zone.js:138
  push../node_modules/@angular/core/fesm5/core.js.NgZone.runOutsideAngular @ core.js:4030
  push../node_modules/@angular/core/fesm5/core.js.ApplicationRef.tick @ core.js:5102
  (anonymous) @ core.js:4938
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:388
  onInvoke @ core.js:4071
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:387
  push../node_modules/zone.js/dist/zone.js.Zone.run @ zone.js:138
  push../node_modules/@angular/core/fesm5/core.js.NgZone.run @ core.js:3927
  next @ core.js:4938
  schedulerFn @ core.js:3721
  push../node_modules/rxjs/_esm5/internal/Subscriber.js.SafeSubscriber.__tryOrUnsub @ Subscriber.js:253
  push../node_modules/rxjs/_esm5/internal/Subscriber.js.SafeSubscriber.next @ Subscriber.js:191
  push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber._next @ Subscriber.js:129
  push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber.next @ Subscriber.js:93
  push../node_modules/rxjs/_esm5/internal/Subject.js.Subject.next @ Subject.js:53
  push../node_modules/@angular/core/fesm5/core.js.EventEmitter.emit @ core.js:3713
  checkStable @ core.js:4040
  onHasTask @ core.js:4084
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.hasTask @ zone.js:441
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate._updateTaskCount @ zone.js:461
  push../node_modules/zone.js/dist/zone.js.Zone._updateTaskCount @ zone.js:285
  push../node_modules/zone.js/dist/zone.js.Zone.runTask @ zone.js:205
  drainMicroTaskQueue @ zone.js:595
  push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask @ zone.js:500
  ZoneTask.invoke @ zone.js:485
  timer @ zone.js:2054
  setTimeout (async)
  scheduleTask @ zone.js:2075
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:407
  push../node_modules/zone.js/dist/zone.js.Zone.scheduleTask @ zone.js:232
  push../node_modules/zone.js/dist/zone.js.Zone.scheduleMacroTask @ zone.js:255
  scheduleMacroTaskWithCurrentZone @ zone.js:1114
  (anonymous) @ zone.js:2090
  proto.(anonymous function) @ zone.js:1394
  push../node_modules/@firebase/firestore/dist/index.cjs.js.AsyncObserver.scheduleEvent @ index.cjs.js:15061
  push../node_modules/@firebase/firestore/dist/index.cjs.js.AsyncObserver.next @ index.cjs.js:15050
  push../node_modules/@firebase/firestore/dist/index.cjs.js.QueryListener.raiseInitialEvent @ index.cjs.js:7610
  push../node_modules/@firebase/firestore/dist/index.cjs.js.QueryListener.onViewSnapshot @ index.cjs.js:7550
  push../node_modules/@firebase/firestore/dist/index.cjs.js.EventManager.onChange @ index.cjs.js:7487
  (anonymous) @ index.cjs.js:8572
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:388
  push../node_modules/zone.js/dist/zone.js.Zone.run @ zone.js:138
  (anonymous) @ zone.js:872
  push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:421
  push../node_modules/zone.js/dist/zone.js.Zone.runTask @ zone.js:188
  drainMicroTaskQueue @ zone.js:595
  push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask @ zone.js:500
  invokeTask @ zone.js:1540
  globalZoneAwareCallback @ zone.js:1566
  PacientesComponent.html:81 ERROR CONTEXT DebugContext_ {view: {…}, nodeIndex: 4, nodeDef: {…}, elDef: {…}, elView: {…}}
  </code></pre>