Allow registered applications to hide Kibana chrome (elastic#49795)

* Allow registered applications to hide Kibana chrome

* Fix bug in flipped value of application chromeHidden

* Add additional test for app chrome hidden versus chrome visibility

* Rename chromeHidden to chromeless

* Default chrome service app hidden observable to same value as force hidden

* Consolidate force hiding in chrome, add functional tests

* Move chromeless flag to App interface to prevent legacy applications from specifying

* Address review nits to improve separation

docs/development/core/public/kibana-plugin-public.app.chromeless.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-public](./kibana-plugin-public.md) &gt; [App](./kibana-plugin-public.app.md) &gt; [chromeless](./kibana-plugin-public.app.chromeless.md)
+
+## App.chromeless property
+
+Hide the UI chrome when the application is mounted. Defaults to `false`<!-- -->. Takes precedence over chrome service visibility settings.
+
+<b>Signature:</b>
+
+```typescript
+chromeless?: boolean;
+```

docs/development/core/public/kibana-plugin-public.app.md

@@ -16,5 +16,6 @@ export interface App extends AppBase
 
 |  Property | Type | Description |
 |  --- | --- | --- |
+|  [chromeless](./kibana-plugin-public.app.chromeless.md) | <code>boolean</code> | Hide the UI chrome when the application is mounted. Defaults to <code>false</code>. Takes precedence over chrome service visibility settings. |
 |  [mount](./kibana-plugin-public.app.mount.md) | <code>(context: AppMountContext, params: AppMountParameters) =&gt; AppUnmount &#124; Promise&lt;AppUnmount&gt;</code> | A mount function called when the user navigates to this app's route. |
 

docs/development/core/public/kibana-plugin-public.appmountparameters.appbasepath.md

@@ -21,12 +21,13 @@ How to configure react-router with a base path:
 export class MyPlugin implements Plugin {
   setup({ application }) {
     application.register({
-    id: 'my-app',
-    async mount(context, params) {
-      const { renderApp } = await import('./application');
-      return renderApp(context, params);
-    },
-  });
+     id: 'my-app',
+     async mount(context, params) {
+       const { renderApp } = await import('./application');
+       return renderApp(context, params);
+     },
+   });
+ }
 }
 
 ```

src/core/public/application/types.ts

@@ -80,6 +80,12 @@ export interface App extends AppBase {
    * @returns An unmounting function that will be called to unmount the application.
    */
   mount: (context: AppMountContext, params: AppMountParameters) => AppUnmount | Promise<AppUnmount>;
+
+  /**
+   * Hide the UI chrome when the application is mounted. Defaults to `false`.
+   * Takes precedence over chrome service visibility settings.
+   */
+  chromeless?: boolean;
 }
 
 /** @internal */
@@ -145,12 +151,13 @@ export interface AppMountParameters {
    * export class MyPlugin implements Plugin {
    *   setup({ application }) {
    *     application.register({
-   *     id: 'my-app',
-   *     async mount(context, params) {
-   *       const { renderApp } = await import('./application');
-   *       return renderApp(context, params);
-   *     },
-   *   });
+   *      id: 'my-app',
+   *      async mount(context, params) {
+   *        const { renderApp } = await import('./application');
+   *        return renderApp(context, params);
+   *      },
+   *    });
+   *  }
    * }
    * ```
    *