diff --git a/packages/core/src/testability/testability.ts b/packages/core/src/testability/testability.ts
index 664ffd11a5..b92cd8af4f 100644
--- a/packages/core/src/testability/testability.ts
+++ b/packages/core/src/testability/testability.ts
@@ -25,10 +25,15 @@ export declare interface PublicTestability {
 // Angular internal, not intended for public API.
 export interface PendingMacrotask {
   source: string;
-  isPeriodic: boolean;
-  delay?: number;
   creationLocation: Error;
-  xhr?: XMLHttpRequest;
+  runCount?: number;
+  data: TaskData;
+}
+
+export interface TaskData {
+  target?: XMLHttpRequest;
+  delay?: number;
+  isPeriodic?: boolean;
 }
 
 // Angular internal, not intended for public API.
@@ -152,17 +157,14 @@ export class Testability implements PublicTestability {
       return [];
     }
 
+    // Copy the tasks data so that we don't leak tasks.
     return this.taskTrackingZone.macroTasks.map((t: Task) => {
       return {
         source: t.source,
-        isPeriodic: t.data.isPeriodic,
-        delay: t.data.delay,
         // From TaskTrackingZone:
         // https://github.com/angular/zone.js/blob/master/lib/zone-spec/task-tracking.ts#L40
         creationLocation: (t as any).creationLocation as Error,
-        // Added by Zones for XHRs
-        // https://github.com/angular/zone.js/blob/master/lib/browser/browser.ts#L133
-        xhr: (t.data as any).target
+        data: t.data
       };
     });
   }
diff --git a/packages/core/test/testability/testability_spec.ts b/packages/core/test/testability/testability_spec.ts
index 7004eeabce..6acd7884f3 100644
--- a/packages/core/test/testability/testability_spec.ts
+++ b/packages/core/test/testability/testability_spec.ts
@@ -143,9 +143,9 @@ class MockNgZone extends NgZone {
              const tasks = execute.calls.mostRecent().args[1] as PendingMacrotask[];
 
              expect(tasks.length).toEqual(1);
-             expect(tasks[0].delay).toEqual(1000);
+             expect(tasks[0].data.delay).toEqual(1000);
              expect(tasks[0].source).toEqual('setTimeout');
-             expect(tasks[0].isPeriodic).toEqual(false);
+             expect(tasks[0].data.isPeriodic).toEqual(false);
 
              clearTimeout(id);
            }));
@@ -207,11 +207,11 @@ class MockNgZone extends NgZone {
              expect(execute).toHaveBeenCalled();
 
              const update1 = updateCallback.calls.all()[0].args[0] as PendingMacrotask[];
-             expect(update1[0].delay).toEqual(500);
+             expect(update1[0].data.delay).toEqual(500);
 
              const update2 = updateCallback.calls.all()[1].args[0] as PendingMacrotask[];
-             expect(update2[0].delay).toEqual(500);
-             expect(update2[1].delay).toEqual(300);
+             expect(update2[0].data.delay).toEqual(500);
+             expect(update2[1].data.delay).toEqual(300);
            }));
 
         it('cancels the done callback if the update callback returns true', fakeAsync(() => {
diff --git a/packages/examples/core/testability/ts/whenStable/e2e_test/testability_example_spec.ts b/packages/examples/core/testability/ts/whenStable/e2e_test/testability_example_spec.ts
index a913d8c75c..544914552b 100644
--- a/packages/examples/core/testability/ts/whenStable/e2e_test/testability_example_spec.ts
+++ b/packages/examples/core/testability/ts/whenStable/e2e_test/testability_example_spec.ts
@@ -30,7 +30,7 @@ describe('testability example', () => {
 
       browser.driver.executeAsyncScript(waitWithResultScript).then((result: any[]) => {
         let pendingTask = result[0];
-        expect(pendingTask.delay).toEqual(5000);
+        expect(pendingTask.data.delay).toEqual(5000);
         expect(pendingTask.source).toEqual('setTimeout');
         expect(element(by.css('.status')).getText()).not.toContain('done');
         done();