Bug 1811290 - [cdp] Implement Target.getBrowserContexts r=webdriver-reviewers,whimboo

Depends on D168203

Differential Revision: https://phabricator.services.mozilla.com/D167293

remote/cdp/domains/parent/Target.sys.mjs

@@ -19,23 +19,31 @@ ChromeUtils.defineESModuleGetters(lazy, {
 let browserContextIds = 1;
 
 export class Target extends Domain {
+  #browserContextIds;
+
   constructor(session) {
     super(session);
 
+    this.#browserContextIds = new Set();
+
     this._onTargetCreated = this._onTargetCreated.bind(this);
     this._onTargetDestroyed = this._onTargetDestroyed.bind(this);
   }
 
   getBrowserContexts() {
-    return {
-      browserContextIds: [],
-    };
+    const browserContextIds = lazy.ContextualIdentityService.getPublicUserContextIds().filter(
+      id => this.#browserContextIds.has(id)
+    );
+
+    return { browserContextIds };
   }
 
   createBrowserContext() {
     const identity = lazy.ContextualIdentityService.create(
       "remote-agent-" + browserContextIds++
     );
+
+    this.#browserContextIds.add(identity.userContextId);
     return { browserContextId: identity.userContextId };
   }
 
@@ -44,6 +52,8 @@ export class Target extends Domain {
 
     lazy.ContextualIdentityService.remove(browserContextId);
     lazy.ContextualIdentityService.closeContainerTabs(browserContextId);
+
+    this.#browserContextIds.delete(browserContextId);
   }
 
   getTargets() {

remote/cdp/test/browser/target/browser_browserContext.js

@@ -12,8 +12,29 @@ add_task(async function({ CDP }) {
   const { Target } = client;
   await getDiscoveredTargets(Target);
 
+  // Test if Target.getBrowserContexts is empty before creatinga ny
+  const {
+    browserContextIds: browserContextIdsBefore,
+  } = await Target.getBrowserContexts();
+
+  is(
+    browserContextIdsBefore.length,
+    0,
+    "No browser context is open by default"
+  );
+
   const { browserContextId } = await Target.createBrowserContext();
 
+  // Test if Target.getBrowserContexts includes the context we just created
+  const { browserContextIds } = await Target.getBrowserContexts();
+
+  is(browserContextIds.length, 1, "Got expected length of browser contexts");
+  is(
+    browserContextIds[0],
+    browserContextId,
+    "Got expected browser context id from getBrowserContexts"
+  );
+
   const targetCreated = Target.targetCreated();
   const { targetId } = await Target.createTarget({ browserContextId });
   ok(!!targetId, "Target.createTarget returns a non-empty target id");
@@ -34,6 +55,17 @@ add_task(async function({ CDP }) {
   // Releasing the browser context is going to remove the tab opened when calling createTarget
   await Target.disposeBrowserContext({ browserContextId });
 
+  // Test if Target.getBrowserContexts now is empty
+  const {
+    browserContextIds: browserContextIdsAfter,
+  } = await Target.getBrowserContexts();
+
+  is(
+    browserContextIdsAfter.length,
+    0,
+    "After closing all browser contexts none is available anymore"
+  );
+
   await client.close();
   info("The client is closed");
 });