fixup! fix(cdk-experimental/menu): move shared menu logic to base class

Author: mmalerba

src/cdk-experimental/menu/menu-base.ts

@@ -19,13 +19,13 @@ import {
   QueryList,
 } from '@angular/core';
 import {FocusKeyManager, FocusOrigin} from '@angular/cdk/a11y';
-import {CdkMenuItem} from '@angular/cdk-experimental/menu/menu-item';
+import {CdkMenuItem} from './menu-item';
 import {merge, Subject} from 'rxjs';
 import {Directionality} from '@angular/cdk/bidi';
 import {mapTo, mergeAll, mergeMap, startWith, switchMap, takeUntil} from 'rxjs/operators';
-import {MENU_STACK, MenuStack, MenuStackItem} from '@angular/cdk-experimental/menu/menu-stack';
-import {Menu} from '@angular/cdk-experimental/menu/menu-interface';
-import {PointerFocusTracker} from '@angular/cdk-experimental/menu/pointer-focus-tracker';
+import {MENU_STACK, MenuStack, MenuStackItem} from './menu-stack';
+import {Menu} from './menu-interface';
+import {PointerFocusTracker} from './pointer-focus-tracker';
 
 @Directive()
 export abstract class CdkMenuBase

src/cdk-experimental/menu/menu.ts

@@ -15,7 +15,6 @@ import {
   Inject,
   NgZone,
   OnDestroy,
-  OnInit,
   Optional,
   Output,
   QueryList,