Add WebviewView.description

Allow configuring the description for webview views.

This is rendered next to the title in a less prominently in the title

src/vs/vscode.proposed.d.ts

@@ -2062,6 +2062,11 @@ declare module 'vscode' {
 		 */
 		title?: string;
 
+		/**
+		 * Human-readable string which is rendered less prominently in the title.
+		 */
+		description?: string;
+
 		/**
 		 * Event fired when the view is disposed.
 		 *

src/vs/workbench/api/browser/mainThreadWebviewViews.ts

@@ -29,13 +29,15 @@ export class MainThreadWebviewsViews extends Disposable implements extHostProtoc
 	}
 
 	public $setWebviewViewTitle(handle: extHostProtocol.WebviewHandle, value: string | undefined): void {
-		const webviewView = this._webviewViews.get(handle);
-		if (!webviewView) {
-			throw new Error('unknown webview view');
-		}
+		const webviewView = this.getWebviewView(handle);
 		webviewView.title = value;
 	}
 
+	public $setWebviewViewDescription(handle: extHostProtocol.WebviewHandle, value: string | undefined): void {
+		const webviewView = this.getWebviewView(handle);
+		webviewView.description = value;
+	}
+
 	public $registerWebviewViewProvider(viewType: string, options?: { retainContextWhenHidden?: boolean }): void {
 		if (this._webviewViewProviders.has(viewType)) {
 			throw new Error(`View provider for ${viewType} already registered`);
@@ -89,5 +91,13 @@ export class MainThreadWebviewsViews extends Disposable implements extHostProtoc
 		provider.dispose();
 		this._webviewViewProviders.delete(viewType);
 	}
+
+	private getWebviewView(handle: string): WebviewView {
+		const webviewView = this._webviewViews.get(handle);
+		if (!webviewView) {
+			throw new Error('unknown webview view');
+		}
+		return webviewView;
+	}
 }
 

src/vs/workbench/api/common/extHost.protocol.ts

@@ -640,6 +640,7 @@ export interface MainThreadWebviewViewsShape extends IDisposable {
 	$unregisterWebviewViewProvider(viewType: string): void;
 
 	$setWebviewViewTitle(handle: WebviewHandle, value: string | undefined): void;
+	$setWebviewViewDescription(handle: WebviewHandle, value: string | undefined): void;
 }
 
 export interface WebviewPanelViewStateData {

src/vs/workbench/api/common/extHostWebviewView.ts

@@ -23,6 +23,7 @@ class ExtHostWebviewView extends Disposable implements vscode.WebviewView {
 	#isDisposed = false;
 	#isVisible: boolean;
 	#title: string | undefined;
+	#description: string | undefined;
 
 	constructor(
 		handle: extHostProtocol.WebviewHandle,
@@ -70,6 +71,19 @@ class ExtHostWebviewView extends Disposable implements vscode.WebviewView {
 		}
 	}
 
+	public get description(): string | undefined {
+		this.assertNotDisposed();
+		return this.#description;
+	}
+
+	public set description(value: string | undefined) {
+		this.assertNotDisposed();
+		if (this.#description !== value) {
+			this.#description = value;
+			this.#proxy.$setWebviewViewDescription(this.#handle, value);
+		}
+	}
+
 	public get visible(): boolean { return this.#isVisible; }
 
 	public get webview(): vscode.Webview { return this.#webview; }

src/vs/workbench/contrib/webviewView/browser/webviewViewPane.ts

@@ -23,7 +23,7 @@ import { IViewletViewOptions } from 'vs/workbench/browser/parts/views/viewsViewl
 import { Memento, MementoObject } from 'vs/workbench/common/memento';
 import { IViewDescriptorService } from 'vs/workbench/common/views';
 import { IWebviewService, WebviewOverlay } from 'vs/workbench/contrib/webview/browser/webview';
-import { IWebviewViewService } from 'vs/workbench/contrib/webviewView/browser/webviewViewService';
+import { IWebviewViewService, WebviewView } from 'vs/workbench/contrib/webviewView/browser/webviewViewService';
 import { IExtensionService } from 'vs/workbench/services/extensions/common/extensions';
 
 declare const ResizeObserver: any;
@@ -158,13 +158,19 @@ export class WebviewViewPane extends ViewPane {
 				await this.extensionService.activateByEvent(`onView:${this.id}`);
 
 				let self = this;
-				await this.webviewViewService.resolve(this.id, {
+				const webviewView: WebviewView = {
 					webview,
 					onDidChangeVisibility: this.onDidChangeBodyVisibility,
 					onDispose: this.onDispose,
+
 					get title() { return self.title; },
-					set title(value: string) { self.updateTitle(value); }
-				}, source.token);
+					set title(value: string) { self.updateTitle(value); },
+
+					get description(): string | undefined { return self.titleDescription; },
+					set description(value: string | undefined) { self.updateTitleDescription(value); },
+				};
+
+				await this.webviewViewService.resolve(this.id, webviewView, source.token);
 			});
 		}
 	}

src/vs/workbench/contrib/webviewView/browser/webviewViewService.ts

@@ -13,6 +13,7 @@ export const IWebviewViewService = createDecorator<IWebviewViewService>('webview
 
 export interface WebviewView {
 	title?: string;
+	description?: string;
 
 	readonly webview: WebviewOverlay;