feature: webview without service worker

[SimonSiefke]

fix #326331

[Copilot]

Pull request overview

Adds an opt-in, Electron-only single-iframe webview loader that avoids service workers while retaining the legacy browser path.

Changes:

• Adds proposed API gating and direct webview URI routing.
• Implements Electron protocol handling, resource streaming, CSP transformation, and iframe messaging.
• Adds tests, a manual test extension, and an implementation plan.

Reviewed changes

Copilot reviewed 24 out of 26 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.webviewNoServiceWorker.d.ts	Declares the proposal.
src/vs/workbench/contrib/webviewView/browser/webviewViewPane.ts	Enables direct loading for eligible views.
src/vs/workbench/contrib/webview/test/browser/resourceLoading.test.ts	Tests direct resource URIs.
src/vs/workbench/contrib/webview/electron-browser/webviewElement.ts	Implements the single-iframe loader.
src/vs/workbench/contrib/webview/common/webview.ts	Adds direct resource routes.
src/vs/workbench/contrib/webview/browser/webviewElement.ts	Adds direct-loader lifecycle hooks.
src/vs/workbench/contrib/webview/browser/webview.ts	Extends webview metadata.
src/vs/workbench/contrib/webview/browser/resourceLoading.ts	Adds canonical-path validation.
src/vs/workbench/contrib/webview/browser/overlayWebview.ts	Propagates resource identifiers.
src/vs/workbench/api/test/browser/extHostWebview.test.ts	Tests proposal gating.
src/vs/workbench/api/common/extHostWebview.ts	Selects direct routing on desktop.
src/vs/workbench/api/common/extHost.protocol.ts	Extends protocol metadata.
src/vs/workbench/api/common/extHost.api.impl.ts	Passes UI kind to webviews.
src/vs/workbench/api/browser/mainThreadWebviews.ts	Assigns and revives routing data.
src/vs/platform/webview/electron-main/webviewProtocolProvider.ts	Serves direct documents and resources.
src/vs/platform/webview/electron-main/webviewMainService.ts	Bridges protocol requests over IPC.
src/vs/platform/webview/common/webviewManagerService.ts	Defines direct-loader IPC contracts.
src/vs/platform/extensions/common/extensionsApiProposals.ts	Registers the proposal.
src/vs/code/electron-main/app.ts	Authorizes requests and maps ports.
src/vs/code/electron-browser/workbench/workbench.html	Allows the Trusted Types policy.
src/vs/code/electron-browser/workbench/workbench-dev.html	Allows the development policy.
implementation-plan.md	Documents the design and test plan.
extensions/webview-no-service-worker/package.json	Declares the manual test extension.
extensions/webview-no-service-worker/media/style.css	Styles its test webview.
extensions/webview-no-service-worker/media/image.svg	Adds its test image.
extensions/webview-no-service-worker/extension.js	Implements the test panel.

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

@deepak1556

Matched files:

• src/vs/code/electron-browser/workbench/workbench-dev.html
• src/vs/code/electron-browser/workbench/workbench.html
• src/vs/code/electron-main/app.ts