address some comments

Author: mmalerba

src/cdk/collections/data-source.ts

@@ -7,7 +7,7 @@
  */
 
 import {Observable} from 'rxjs/Observable';
-import {of} from 'rxjs/observable/of';
+import {of as observableOf} from 'rxjs/observable/of';
 import {CollectionViewer} from './collection-viewer';
 
 
@@ -38,7 +38,7 @@ export class ArrayDataSource<T> implements DataSource<T> {
   constructor(private _data: T[]) {}
 
   connect(): Observable<T[]> {
-    return of(this._data);
+    return observableOf(this._data);
   }
 
   disconnect() {}

src/cdk/scrolling/for-of.ts

@@ -172,7 +172,11 @@ export class CdkForOf<T> implements CollectionViewer, DoCheck, OnDestroy {
   ngDoCheck() {
     if (this._differ && this._needsUpdate) {
       const changes = this._differ.diff(this._renderedItems);
-      this._applyChanges(changes);
+      if (!changes) {
+        this._updateContext();
+      } else {
+        this._applyChanges(changes);
+      }
       this._needsUpdate = false;
     }
   }
@@ -208,19 +212,18 @@ export class CdkForOf<T> implements CollectionViewer, DoCheck, OnDestroy {
     return newDs.connect(this);
   }
 
-  /** Apply changes to the DOM. */
-  private _applyChanges(changes: IterableChanges<T> | null) {
-    // If there are no changes, just update the index and count on the view context and be done.
-    if (!changes) {
-      for (let i = 0, len = this._viewContainerRef.length; i < len; i++) {
-        let view = this._viewContainerRef.get(i) as EmbeddedViewRef<CdkForOfContext<T>>;
-        view.context.index = this._renderedRange.start + i;
-        view.context.count = this._data.length;
-        view.detectChanges();
-      }
-      return;
+  /** Update the `CdkForOfContext` for all views. */
+  private _updateContext() {
+    for (let i = 0, len = this._viewContainerRef.length; i < len; i++) {
+      let view = this._viewContainerRef.get(i) as EmbeddedViewRef<CdkForOfContext<T>>;
+      view.context.index = this._renderedRange.start + i;
+      view.context.count = this._data.length;
+      view.detectChanges();
     }
+  }
 
+  /** Apply changes to the DOM. */
+  private _applyChanges(changes: IterableChanges<T>) {
     // Detach all of the views and add them into an array to preserve their original order.
     const previousViews: EmbeddedViewRef<CdkForOfContext<T>>[] = [];
     for (let i = 0, len = this._viewContainerRef.length; i < len; i++) {
@@ -255,6 +258,11 @@ export class CdkForOf<T> implements CollectionViewer, DoCheck, OnDestroy {
     }
 
     // We now have a full list of everything to be inserted, so go ahead and insert them.
+    this._insertViews(insertTuples);
+  }
+
+  /** Insert the RecordViewTuples into the container element. */
+  private _insertViews(insertTuples: RecordViewTuple<T>[]) {
     for (let i = 0, len = insertTuples.length; i < len; i++) {
       let {view, record} = insertTuples[i];
       if (view) {

src/cdk/scrolling/virtual-scroll-viewport.ts

@@ -78,8 +78,8 @@ export class CdkVirtualScrollViewport implements OnInit, DoCheck, OnDestroy {
   private _renderedRange: Range = {start: 0, end: 0};
 
   /** The offset of the rendered portion of the data from the start. */
-  get renderedContentOffset() { return this._renderedContentOffset; }
-  set renderedContentOffset(offset) {
+  get renderedContentOffset(): number { return this._renderedContentOffset; }
+  set renderedContentOffset(offset: number) {
     if (this._renderedContentOffset != offset) {
       this._ngZone.run(() => {
         this._renderedContentOffset = offset;
@@ -148,8 +148,10 @@ export class CdkVirtualScrollViewport implements OnInit, DoCheck, OnDestroy {
     Promise.resolve().then(() => {
       this._viewportSize = this.orientation === 'horizontal' ?
           this.elementRef.nativeElement.clientWidth : this.elementRef.nativeElement.clientHeight;
-      fromEvent(this.elementRef.nativeElement, 'scroll').subscribe(() => {
-        this._markScrolled();
+      this._ngZone.runOutsideAngular(() => {
+        fromEvent(this.elementRef.nativeElement, 'scroll').subscribe(() => {
+          this._markScrolled();
+        });
       });
       this._scrollStrategy.init(this);
       this._scrollStrategyInited = true;