Earpiece switcher and overlay (#3347)

* Add a global control for toggling earpiece mode

This will be used by Element X to show an earpiece toggle button in the header.

* Add an earpiece overlay


* Fix header
The header needs to be passed forward as a string to some components and as a bool (hideHeader) to others.
Also use a enum instead of string options.

* fix top clipping with header


* hide app bar in pip

* revert android overlay app_bar

* Modernize AppBarContext

* Style header icon color as desired and switch earpice/speaker icon

* fix initial selection when using controlled media

* Add "Back to video" button

* fix tests

* remove dead code

* add snapshot test

* fix back to video button

* Request capability to learn the room name

We now need the room name in order to implement the mobile (widget-based) designs with the app bar.

* Test the CallViewModel output switcher directly

---------

Co-authored-by: Timo <toger5@hotmail.de>

src/AppBar.tsx

@@ -0,0 +1,134 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  createContext,
+  type FC,
+  type MouseEvent,
+  type ReactNode,
+  use,
+  useCallback,
+  useEffect,
+  useMemo,
+  useState,
+} from "react";
+import { Heading, IconButton, Tooltip } from "@vector-im/compound-web";
+import {
+  ArrowLeftIcon,
+  CollapseIcon,
+} from "@vector-im/compound-design-tokens/assets/web/icons";
+import { useTranslation } from "react-i18next";
+
+import { Header, LeftNav, RightNav } from "./Header";
+import { platform } from "./Platform";
+import styles from "./AppBar.module.css";
+
+interface AppBarContext {
+  setTitle: (value: string) => void;
+  setSecondaryButton: (value: ReactNode) => void;
+  setHidden: (value: boolean) => void;
+}
+
+const AppBarContext = createContext<AppBarContext | null>(null);
+
+interface Props {
+  children: ReactNode;
+}
+
+/**
+ * A "top app bar" featuring a back button, title and possibly a secondary
+ * button, similar to what you might see in mobile apps.
+ */
+export const AppBar: FC<Props> = ({ children }) => {
+  const { t } = useTranslation();
+  const BackIcon = platform === "ios" ? CollapseIcon : ArrowLeftIcon;
+  const onBackClick = useCallback((e: MouseEvent) => {
+    e.preventDefault();
+    window.controls.onBackButtonPressed?.();
+  }, []);
+
+  const [title, setTitle] = useState<string>("");
+  const [hidden, setHidden] = useState<boolean>(false);
+  const [secondaryButton, setSecondaryButton] = useState<ReactNode>(null);
+  const context = useMemo(
+    () => ({ setTitle, setSecondaryButton, setHidden }),
+    [setTitle, setHidden, setSecondaryButton],
+  );
+
+  return (
+    <>
+      <div
+        style={{ display: hidden ? "none" : "block" }}
+        className={styles.bar}
+      >
+        <Header>
+          <LeftNav>
+            <Tooltip label={t("common.back")}>
+              <IconButton onClick={onBackClick}>
+                <BackIcon />
+              </IconButton>
+            </Tooltip>
+          </LeftNav>
+          {title && (
+            <Heading
+              type="body"
+              size="lg"
+              weight={platform === "android" ? "medium" : "semibold"}
+            >
+              {title}
+            </Heading>
+          )}
+          <RightNav>{secondaryButton}</RightNav>
+        </Header>
+      </div>
+      <AppBarContext value={context}>{children}</AppBarContext>
+    </>
+  );
+};
+
+/**
+ * React hook which sets the title to be shown in the app bar, if present. It is
+ * an error to call this hook from multiple sites in the same component tree.
+ */
+export function useAppBarTitle(title: string): void {
+  const setTitle = use(AppBarContext)?.setTitle;
+  useEffect(() => {
+    if (setTitle !== undefined) {
+      setTitle(title);
+      return (): void => setTitle("");
+    }
+  }, [title, setTitle]);
+}
+
+/**
+ * React hook which sets the title to be shown in the app bar, if present. It is
+ * an error to call this hook from multiple sites in the same component tree.
+ */
+export function useAppBarHidden(hidden: boolean): void {
+  const setHidden = use(AppBarContext)?.setHidden;
+  useEffect(() => {
+    if (setHidden !== undefined) {
+      setHidden(hidden);
+      return (): void => setHidden(false);
+    }
+  }, [setHidden, hidden]);
+}
+
+/**
+ * React hook which sets the secondary button to be shown in the app bar, if
+ * present. It is an error to call this hook from multiple sites in the same
+ * component tree.
+ */
+export function useAppBarSecondaryButton(button: ReactNode): void {
+  const setSecondaryButton = use(AppBarContext)?.setSecondaryButton;
+  useEffect(() => {
+    if (setSecondaryButton !== undefined) {
+      setSecondaryButton(button);
+      return (): void => setSecondaryButton("");
+    }
+  }, [button, setSecondaryButton]);
+}