diff --git a/src/cdk/overlay/overlay-directives.ts b/src/cdk/overlay/overlay-directives.ts
index 0cb124b9ae7e..99b30b4d345a 100644
--- a/src/cdk/overlay/overlay-directives.ts
+++ b/src/cdk/overlay/overlay-directives.ts
@@ -339,7 +339,7 @@ export class CdkConnectedOverlay implements OnDestroy, OnChanges {
     }
 
     this._position.withDirection(this.dir);
-    this._overlayRef.setDirection(this.dir);
+    this._overlayRef.getConfig().direction = this.dir;
     this._document.addEventListener('keydown', this._escapeListener);
 
     if (!this._overlayRef.hasAttached()) {
diff --git a/src/cdk/overlay/overlay-ref.ts b/src/cdk/overlay/overlay-ref.ts
index c1be7f8b78b2..22d2474e43d5 100644
--- a/src/cdk/overlay/overlay-ref.ts
+++ b/src/cdk/overlay/overlay-ref.ts
@@ -6,9 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Direction} from '@angular/cdk/bidi';
-import {ComponentPortal, Portal, PortalOutlet, TemplatePortal} from '@angular/cdk/portal';
-import {ComponentRef, EmbeddedViewRef, NgZone} from '@angular/core';
+import {Portal, PortalOutlet} from '@angular/cdk/portal';
+import {NgZone} from '@angular/core';
 import {Observable} from 'rxjs/Observable';
 import {take} from 'rxjs/operators/take';
 import {Subject} from 'rxjs/Subject';
@@ -16,11 +15,6 @@ import {OverlayKeyboardDispatcher} from './keyboard/overlay-keyboard-dispatcher'
 import {OverlayConfig} from './overlay-config';
 
 
-/** An object where all of its properties cannot be written. */
-export type ImmutableObject<T> = {
-  readonly [P in keyof T]: T[P];
-};
-
 /**
  * Reference to an overlay that has been created with the Overlay service.
  * Used to manipulate or dispose of said overlay.
@@ -37,7 +31,7 @@ export class OverlayRef implements PortalOutlet {
   constructor(
       private _portalOutlet: PortalOutlet,
       private _pane: HTMLElement,
-      private _config: ImmutableObject<OverlayConfig>,
+      private _config: OverlayConfig,
       private _ngZone: NgZone,
       private _keyboardDispatcher: OverlayKeyboardDispatcher) {
 
@@ -51,10 +45,6 @@ export class OverlayRef implements PortalOutlet {
     return this._pane;
   }
 
-  attach<T>(portal: ComponentPortal<T>): ComponentRef<T>;
-  attach<T>(portal: TemplatePortal<T>): EmbeddedViewRef<T>;
-  attach(portal: any): any;
-
   /**
    * Attaches content, given via a Portal, to the overlay.
    * If the overlay is configured to have a backdrop, it will be created.
@@ -71,8 +61,8 @@ export class OverlayRef implements PortalOutlet {
 
     // Update the pane element with the given configuration.
     this._updateStackingOrder();
-    this._updateElementSize();
-    this._updateElementDirection();
+    this.updateSize();
+    this.updateDirection();
 
     if (this._config.scrollStrategy) {
       this._config.scrollStrategy.enable();
@@ -208,25 +198,13 @@ export class OverlayRef implements PortalOutlet {
     }
   }
 
-  /** Update the size properties of the overlay. */
-  updateSize(sizeConfig: OverlaySizeConfig) {
-    this._config = {...this._config, ...sizeConfig};
-    this._updateElementSize();
-  }
-
-  /** Sets the LTR/RTL direction for the overlay. */
-  setDirection(dir: Direction) {
-    this._config = {...this._config, direction: dir};
-    this._updateElementDirection();
-  }
-
   /** Updates the text direction of the overlay panel. */
-  private _updateElementDirection() {
+  private updateDirection() {
     this._pane.setAttribute('dir', this._config.direction!);
   }
 
-  /** Updates the size of the overlay element based on the overlay config. */
-  private _updateElementSize() {
+  /** Updates the size of the overlay based on the overlay config. */
+  updateSize() {
     if (this._config.width || this._config.width === 0) {
       this._pane.style.width = formatCssUnit(this._config.width);
     }
@@ -275,12 +253,10 @@ export class OverlayRef implements PortalOutlet {
     this._backdropElement.addEventListener('click', () => this._backdropClick.next(null));
 
     // Add class to fade-in the backdrop after one frame.
-    this._ngZone.runOutsideAngular(() => {
-      requestAnimationFrame(() => {
-        if (this._backdropElement) {
-          this._backdropElement.classList.add('cdk-overlay-backdrop-showing');
-        }
-      });
+    requestAnimationFrame(() => {
+      if (this._backdropElement) {
+        this._backdropElement.classList.add('cdk-overlay-backdrop-showing');
+      }
     });
   }
 
@@ -341,14 +317,3 @@ export class OverlayRef implements PortalOutlet {
 function formatCssUnit(value: number | string) {
   return typeof value === 'string' ? value as string : `${value}px`;
 }
-
-
-/** Size properties for an overlay. */
-export interface OverlaySizeConfig {
-  width?: number | string;
-  height?: number | string;
-  minWidth?: number | string;
-  minHeight?: number | string;
-  maxWidth?: number | string;
-  maxHeight?: number | string;
-}
diff --git a/src/cdk/portal/portal.ts b/src/cdk/portal/portal.ts
index 981f12f562e1..911d01a6484c 100644
--- a/src/cdk/portal/portal.ts
+++ b/src/cdk/portal/portal.ts
@@ -181,10 +181,6 @@ export abstract class BasePortalOutlet implements PortalOutlet {
     return !!this._attachedPortal;
   }
 
-  attach<T>(portal: ComponentPortal<T>): ComponentRef<T>;
-  attach<T>(portal: TemplatePortal<T>): EmbeddedViewRef<T>;
-  attach(portal: any): any;
-
   /** Attaches a portal. */
   attach(portal: Portal<any>): any {
     if (!portal) {
diff --git a/src/lib/autocomplete/autocomplete-trigger.ts b/src/lib/autocomplete/autocomplete-trigger.ts
index 1e328390e6be..9abc6c95fafc 100644
--- a/src/lib/autocomplete/autocomplete-trigger.ts
+++ b/src/lib/autocomplete/autocomplete-trigger.ts
@@ -458,7 +458,8 @@ export class MatAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
       this._overlayRef = this._overlay.create(this._getOverlayConfig());
     } else {
       /** Update the panel width, in case the host width has changed */
-      this._overlayRef.updateSize({width: this._getHostWidth()});
+      this._overlayRef.getConfig().width = this._getHostWidth();
+      this._overlayRef.updateSize();
     }
 
     if (this._overlayRef && !this._overlayRef.hasAttached()) {