perf: expect the persistent session on Android snapshot-raw

packages/platform-android/src/snapshot.ts

@@ -479,7 +479,7 @@ async function captureAndroidUiHierarchyFromHelper(params: {
   captureOptions.idleWait = params.idleWait;
   let sessionCapture: AndroidSnapshotHelperOutput | undefined;
   try {
-    sessionCapture = await withDiagnosticTimer(
+    await withDiagnosticTimer(
       ANDROID_SNAPSHOT_HELPER_SESSION_CAPTURE_PHASE,
       async () => (sessionCapture = await captureAndroidSnapshotWithHelperSession(captureOptions)),
       () => ({

scripts/perf/README.md

@@ -44,7 +44,7 @@ At the end, or on SIGINT or SIGTERM, the suite saves the logs to `raw/state/`, s
 Each platform times the normal snapshot path and one forced path.
 
 - iOS: the simulator accessibility bridge answers normal captures. `home-reads/snapshot-forced-tree` pins the XCTest tree backend through the SDK, because the CLI has no flag for it. Only a regular capture honors the pin; a raw capture runs its own backend ladder. The response must name the `tree` backend with the `requested-backend` reason code. The XCTest tree rejects the heavy feed, so the step runs on the home screen.
-- Android: the snapshot helper APK is the only snapshot engine (ADR 0002). Its persistent session answers normal captures. `snapshot-raw-one-shot` restarts the daemon with `AGENT_DEVICE_ANDROID_SNAPSHOT_HELPER_SESSION=0`, so a one-shot `am instrument` capture answers. The harness restarts the daemon without the variable after the step. Both raw captures must reach depth 56. The forced capture must report the `instrumentation` transport.
+- Android: the snapshot helper APK is the only snapshot engine (ADR 0002). Its persistent session answers normal captures. `snapshot-raw-one-shot` restarts the daemon with `AGENT_DEVICE_ANDROID_SNAPSHOT_HELPER_SESSION=0`, so a one-shot `am instrument` capture answers. The harness restarts the daemon without the variable after the step. Both raw captures must reach depth 56. `snapshot-raw` must report the `persistent-session` transport, and the forced capture must report the `instrumentation` transport.
 
 ## Platform parity
 

scripts/perf/suite.test.ts

@@ -100,3 +100,20 @@ test('an Android capture breaks its expectation when another helper transport se
   );
   assert.match(expectationViolation(oneShot, {})!, /unknown transport/);
 });
+
+test('the Android heavy-feed raw capture expects the persistent session to answer', () => {
+  const heavyFeed = suiteFor('android').find((s) => s.id === 'heavy-feed')!;
+  const raw = heavyFeed.steps.find((s) => s.id === 'snapshot-raw')!;
+  assert.match(
+    expectationViolation(raw.expect, { maxDepth: 60, transport: 'instrumentation' })!,
+    /instrumentation transport served the capture, not persistent-session/,
+  );
+  assert.equal(
+    expectationViolation(raw.expect, { maxDepth: 60, transport: 'persistent-session' }),
+    undefined,
+  );
+  const iosRaw = suiteFor('ios')
+    .find((s) => s.id === 'heavy-feed')!
+    .steps.find((s) => s.id === 'snapshot-raw')!;
+  assert.equal(iosRaw.expect?.transport, undefined);
+});

scripts/perf/suite.ts

@@ -373,7 +373,7 @@ export const SUITE: readonly SuiteScenario<SuiteStep>[] = [
       // The fixture renders more than 65 native levels on iOS and 60 on Android.
       step('snapshot-raw', C.snapshot, ['snapshot', '--raw'], {
         expect: { maxDepthAtLeast: 64 },
-        on: { android: { expect: { maxDepthAtLeast: 56 } } },
+        on: { android: { expect: { maxDepthAtLeast: 56, transport: 'persistent-session' } } },
       }),
       step('press-like-selector', C.press, ['press', 'id="heavy-post-0-like"']),
       step('press-like-settle', C.press, ['press', 'id="heavy-post-1-like"', '--settle']),