feat: move a11y, bidi, platform, rxjs, and portal to cdk (#5386)

* feat: move a11y, bidi, platform, and portal to cdk

* lint

* Fix weird rxjs operator typing issue

* Workaround for ngc issue

* debug ie11

* debug ios

* Add directionaltiy reexport

Author: jelbourn

src/cdk/a11y/README.md

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+# LiveAnnouncer
+`LiveAnnouncer` is a service, which announces messages to several screenreaders.
+
+### Methods
+
+| Name |  Description |
+| --- | --- |
+| `announce(message, politeness)` | This announces a text message to the supported screenreaders. <br><br>The politeness parameter sets the `aria-live` attribute on the announcer element |
+
+### Examples
+The service can be injected in a component.
+```ts
+@Component({
+  selector: 'my-component'
+  providers: [LiveAnnouncer]
+})
+export class MyComponent {
+
+ constructor(live: LiveAnnouncer) {
+   live.announce("Hey Google");
+ }
+
+}
+```
+
+### Supported Screenreaders
+- JAWS (Windows)
+- NVDA (Windows)
+- VoiceOver (OSX and iOS)
+- TalkBack (Android)

src/cdk/a11y/activedescendant-key-manager.ts

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+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {QueryList} from '@angular/core';
+import {ListKeyManager, CanDisable} from './list-key-manager';
+
+/**
+ * This is the interface for highlightable items (used by the ActiveDescendantKeyManager).
+ * Each item must know how to style itself as active or inactive and whether or not it is
+ * currently disabled.
+ */
+export interface Highlightable extends CanDisable {
+  setActiveStyles(): void;
+  setInactiveStyles(): void;
+}
+
+export class ActiveDescendantKeyManager extends ListKeyManager<Highlightable> {
+
+  /**
+   * This method sets the active item to the item at the specified index.
+   * It also adds active styles to the newly active item and removes active
+   * styles from the previously active item.
+   */
+  setActiveItem(index: number): void {
+    Promise.resolve().then(() => {
+      if (this.activeItem) {
+        this.activeItem.setInactiveStyles();
+      }
+      super.setActiveItem(index);
+      if (this.activeItem) {
+        this.activeItem.setActiveStyles();
+      }
+    });
+  }
+
+}

src/cdk/a11y/fake-mousedown.ts

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+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * Screenreaders will often fire fake mousedown events when a focusable element
+ * is activated using the keyboard. We can typically distinguish between these faked
+ * mousedown events and real mousedown events using the "buttons" property. While
+ * real mousedowns will indicate the mouse button that was pressed (e.g. "1" for
+ * the left mouse button), faked mousedowns will usually set the property value to 0.
+ */
+export function isFakeMousedownFromScreenReader(event: MouseEvent): boolean {
+  return event.buttons === 0;
+}

src/cdk/a11y/focus-key-manager.ts

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+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {QueryList} from '@angular/core';
+import {ListKeyManager, CanDisable} from './list-key-manager';
+
+/**
+ * This is the interface for focusable items (used by the FocusKeyManager).
+ * Each item must know how to focus itself and whether or not it is currently disabled.
+ */
+export interface Focusable extends CanDisable {
+  focus(): void;
+}
+
+
+export class FocusKeyManager extends ListKeyManager<Focusable> {
+
+  constructor(items: QueryList<Focusable>) {
+    super(items);
+  }
+
+  /**
+   * This method sets the active item to the item at the specified index.
+   * It also adds focuses the newly active item.
+   */
+  setActiveItem(index: number): void {
+    super.setActiveItem(index);
+
+    if (this.activeItem) {
+      this.activeItem.focus();
+    }
+  }
+
+}