[WIP] Add emulate focused page feature for debugging Code OSS

package.nls.json

@@ -47,6 +47,7 @@
   "chrome.label": "Web App (Chrome)",
   "chrome.launch.description": "Launch Chrome to debug a URL",
   "chrome.launch.label": "Chrome: Launch",
+  "browser.emulateFocusedPage": "Emulate a focused page",
   "commands.callersAdd.label": "Exclude Caller",
   "commands.callersAdd.paletteLabel": "Exclude caller from pausing in the current location",
   "commands.callersGoToCaller.label": "Go to caller location",

src/adapter/debugAdapter.ts

@@ -112,6 +112,9 @@ export class DebugAdapter implements IDisposable {
     this.dap.on('prettyPrintSource', params => this._prettyPrintSource(params));
     this.dap.on('locations', params => this._onLocations(params));
     this.dap.on('revealPage', () => this._withThread(thread => thread.revealPage()));
+    this.dap.on('setFocusEmulationEnabled', params =>
+      this._withThread(thread => thread.setFocusEmulationEnabled(params)),
+    );
     this.dap.on(
       'getPerformance',
       () => this._withThread(thread => performanceProvider.retrieve(thread.cdp())),

src/adapter/threads.ts

@@ -190,6 +190,7 @@ export class Thread implements IVariableStoreLocationProvider {
   private _expectedPauseReason?: ExpectedPauseReason;
   private _excludedCallers: readonly Dap.ExcludedCaller[] = [];
   private _enabledCustomBreakpoints?: ReadonlySet<string>;
+  private _focusEmulationEnabled = false;
   /** Last parsed WASM script ID. Set immediately before breaking in {@link _breakOnWasmScriptId} */
   private _lastParsedWasmScriptIds?: string[];
   private readonly stateQueue = new StateQueue();
@@ -453,6 +454,20 @@ export class Thread implements IVariableStoreLocationProvider {
     return {};
   }
 
+  public async setFocusEmulationEnabled(
+    params: Dap.SetFocusEmulationEnabledParams,
+  ): Promise<Dap.SetFocusEmulationEnabledResult> {
+    const enabled = params.enabled ?? !this._focusEmulationEnabled;
+    const emulation = this._cdp.Emulation;
+    if (!emulation) {
+      return { enabled: this._focusEmulationEnabled };
+    }
+
+    await emulation.setFocusEmulationEnabled({ enabled });
+    this._focusEmulationEnabled = enabled;
+    return { enabled: this._focusEmulationEnabled };
+  }
+
   public async completions(
     params: Dap.CompletionsParams,
   ): Promise<Dap.CompletionsResult | Dap.Error> {

src/build/dapCustom.ts

@@ -101,6 +101,29 @@ const dapCustom: JSONSchema4 = {
       required: ['ids', 'xhr'],
     }),
 
+    ...makeRequest(
+      'setFocusEmulationEnabled',
+      'Enables or disables focused page emulation.',
+      {
+        properties: {
+          enabled: {
+            type: 'boolean',
+            description: 'Whether to emulate a focused page. Defaults to toggling the current state.',
+          },
+        },
+        additionalProperties: false,
+      },
+      {
+        properties: {
+          enabled: {
+            type: 'boolean',
+            description: 'Whether focused page emulation is enabled after the request.',
+          },
+        },
+        required: ['enabled'],
+      },
+    ),
+
     ...makeRequest('prettyPrintSource', 'Pretty prints source for debugging.', {
       properties: {
         source: {

src/build/generate-contributions.ts

@@ -1337,6 +1337,11 @@ const commands: ReadonlyArray<{
     title: refString('browser.revealPage'),
     category: 'Debug',
   },
+  {
+    command: Commands.EmulateFocusedPage,
+    title: refString('browser.emulateFocusedPage'),
+    category: 'Debug',
+  },
   {
     command: Commands.DebugLink,
     title: refString('debugLink.label'),
@@ -1447,6 +1452,11 @@ const menus: Menus = {
       command: Commands.RevealPage,
       when: 'false',
     },
+    {
+      command: Commands.EmulateFocusedPage,
+      title: refString('browser.emulateFocusedPage'),
+      when: forBrowserDebugType('debugType', 'inDebugMode'),
+    },
     {
       command: Commands.DebugLink,
       title: refString('debugLink.label'),
@@ -1569,6 +1579,14 @@ const menus: Menus = {
       when: `view == ${CustomViews.EventListenerBreakpoints}`,
       group: 'navigation',
     },
+    {
+      command: Commands.EmulateFocusedPage,
+      when: forBrowserDebugType(
+        'debugType',
+        `view == ${CustomViews.EventListenerBreakpoints} && inDebugMode`,
+      ),
+      group: 'navigation',
+    },
     {
       command: Commands.RemoveAllCustomBreakpoints,
       when: `view == ${CustomViews.EventListenerBreakpoints}`,

src/common/contributionUtils.ts

@@ -47,6 +47,7 @@ export const enum Commands {
   RemoveAllCustomBreakpoints = 'extension.js-debug.removeAllCustomBreakpoints',
   RemoveXHRBreakpoints = 'extension.js-debug.removeXHRBreakpoint',
   RevealPage = 'extension.js-debug.revealPage',
+  EmulateFocusedPage = 'extension.js-debug.emulateFocusedPage',
   RequestCDPProxy = 'extension.js-debug.requestCDPProxy',
   /** Use node-debug's command so existing keybindings work */
   StartWithStopOnEntry = 'extension.node-debug.startWithStopOnEntry',
@@ -121,6 +122,7 @@ const commandsObj: { [K in Commands]: null } = {
   [Commands.RemoveXHRBreakpoints]: null,
   [Commands.RemoveAllCustomBreakpoints]: null,
   [Commands.RevealPage]: null,
+  [Commands.EmulateFocusedPage]: null,
   [Commands.StartProfile]: null,
   [Commands.StopProfile]: null,
   [Commands.ToggleSkipping]: null,
@@ -231,6 +233,7 @@ export interface ICommandTypes {
   [Commands.AutoAttachClearVariables](): void;
   [Commands.AutoAttachToProcess](info: IAutoAttachInfo): void;
   [Commands.RevealPage](sessionId: string): void;
+  [Commands.EmulateFocusedPage](): Promise<void> | void;
   [Commands.DebugLink](link?: string): void;
   [Commands.StartWithStopOnEntry](): void;
   [Commands.RequestCDPProxy](