refactor(cdk/overlay): revert internal workaround (#32374)

Reverts a workaround now that it isn't necessary anymore.

Author: crisbeto

src/cdk/overlay/overlay-ref.ts

@@ -32,6 +32,11 @@ export type ImmutableObject<T> = {
   readonly [P in keyof T]: T[P];
 };
 
+/** Checks if a value is an element. */
+export function isElement(value: any): value is Element {
+  return value && (value as Element).nodeType === 1;
+}
+
 /**
  * Reference to an overlay that has been created with the Overlay service.
  * Used to manipulate or dispose of said overlay.
@@ -409,14 +414,10 @@ export class OverlayRef implements PortalOutlet {
         ? this._positionStrategy?.getPopoverInsertionPoint?.()
         : null;
 
-      if (customInsertionPoint) {
-        if (customInsertionPoint instanceof Element) {
-          customInsertionPoint.after(this._host);
-        } else {
-          if (customInsertionPoint.type === 'parent') {
-            customInsertionPoint.element?.appendChild(this._host);
-          }
-        }
+      if (isElement(customInsertionPoint)) {
+        customInsertionPoint.after(this._host);
+      } else if (customInsertionPoint?.type === 'parent') {
+        customInsertionPoint.element.appendChild(this._host);
       } else {
         this._previousHostParent?.appendChild(this._host);
       }

src/cdk/overlay/overlay.ts

@@ -28,7 +28,7 @@ import {OverlayKeyboardDispatcher} from './dispatchers/overlay-keyboard-dispatch
 import {OverlayOutsideClickDispatcher} from './dispatchers/overlay-outside-click-dispatcher';
 import {OverlayConfig} from './overlay-config';
 import {_CdkOverlayStyleLoader, OverlayContainer} from './overlay-container';
-import {OverlayRef} from './overlay-ref';
+import {isElement, OverlayRef} from './overlay-ref';
 import {OverlayPositionBuilder} from './position/overlay-position-builder';
 import {ScrollStrategyOptions} from './scroll/index';
 
@@ -89,19 +89,14 @@ export function createOverlayRef(injector: Injector, config?: OverlayConfig): Ov
     ? overlayConfig.positionStrategy?.getPopoverInsertionPoint?.()
     : null;
 
-  overlayContainer.getContainerElement().appendChild(host);
-
-  // Note: it's redundant to pass the `host` through the container element above if
-  // it's going to end up at the custom insertion point anyways. We need to do it,
-  // because some internal clients depend on the host passing through the container first.
-  if (customInsertionPoint) {
-    if (customInsertionPoint instanceof Element) {
-      customInsertionPoint.after(host);
-    } else {
-      if (customInsertionPoint.type === 'parent') {
-        customInsertionPoint.element?.appendChild(host);
-      }
-    }
+  if (isElement(customInsertionPoint)) {
+    customInsertionPoint.after(host);
+  } else if (customInsertionPoint?.type === 'parent') {
+    customInsertionPoint.element.appendChild(host);
+  } else {
+    // Note: leave the container for last so that we fall
+    // back to it for unsupported/newly-added values.
+    overlayContainer.getContainerElement().appendChild(host);
   }
 
   return new OverlayRef(

src/cdk/overlay/position/flexible-connected-position-strategy.ts

@@ -22,7 +22,7 @@ import {isElementScrolledOutsideView, isElementClippedByScrolling} from './scrol
 import {coerceCssPixelValue, coerceArray} from '../../coercion';
 import {Platform} from '../../platform';
 import {OverlayContainer} from '../overlay-container';
-import {OverlayRef} from '../overlay-ref';
+import {isElement, OverlayRef} from '../overlay-ref';
 
 // TODO: refactor clipping detection into a separate thing (part of scrolling module)
 // TODO: doesn't handle both flexible width and height when it has to scroll along both axis.
@@ -537,32 +537,17 @@ export class FlexibleConnectedPositionStrategy implements PositionStrategy {
   getPopoverInsertionPoint(): Element | null | {type: 'parent'; element: Element} {
     if (this._popoverLocation === 'global') {
       return null;
+    } else if (this._popoverLocation !== 'inline') {
+      return this._popoverLocation;
     }
 
-    let hostElement: Element | null = null;
-
-    if (this._popoverLocation === 'inline') {
-      if (this._origin instanceof ElementRef) {
-        hostElement = this._origin.nativeElement;
-      } else if (this._origin instanceof Element) {
-        hostElement = this._origin;
-      }
+    if (this._origin instanceof ElementRef) {
+      return this._origin.nativeElement;
+    } else if (isElement(this._origin)) {
+      return this._origin;
     } else {
-      // this._popoverLocation is {type: 'parent', element: Element}
-      hostElement = this._popoverLocation.element;
-    }
-
-    // If the location is 'inline', we're inserting as a sibling.
-    if (this._popoverLocation === 'inline') {
-      return hostElement;
-    }
-
-    // Otherwise we're inserting as a child.
-    if (hostElement) {
-      return {type: 'parent', element: hostElement};
+      return null;
     }
-
-    return null;
   }
 
   /**