Bring the live view connect budget inside the embedder watchdog

images/chromium-headful/client/src/neko/base.ts

@@ -17,6 +17,10 @@ import {
 // only "timeout", so each stage fails on its own bound with its own reason. A
 // bound expiring is terminal rather than retried: a second attempt against the
 // same peer costs the viewer time an embedder can spend on a new session.
+//
+// The bounds are sequential, so they are also a budget: an embedder that gives
+// up on a viewer before the last one expires never sees the reason. The three
+// sum to 23s, and the watchdog in the live-view docs is set above that.
 export type ConnectStage = 'transport' | 'signaling' | 'media'
 
 export const CONNECT_STAGE_TIMEOUT_MS: Record<ConnectStage, number> = {
@@ -32,11 +36,13 @@ export const CONNECT_STAGE_TIMEOUT_MS: Record<ConnectStage, number> = {
   // the remote candidates arrive in the offer — measured 1-16ms direct, ~90ms
   // relay-only. The bound covers through ICE `connected` rather than stopping at
   // `checking`, and the timings above only recorded `checking`: 44 of 130 runs
-  // have no `connected` timestamp, all 30 ap-southeast runs among them. Nothing
-  // measured the stretch the bound now waits on, so 30s is an interim ceiling for
-  // it rather than a calibrated one, to be replaced once per-region timings
-  // through a successful connect exist.
-  media: 30000,
+  // have no `connected` timestamp, all 30 ap-southeast runs among them, so the
+  // stretch this waits on is only partly measured. 5s is a ceiling on that
+  // stretch rather than a calibrated value, and is to be replaced by per-region
+  // timings through a successful connect. It is not 30s: an embedder that
+  // remounts 15s after mount — the example the live-view docs ship — throws the
+  // frame away before a 30s bound could report which stage stalled.
+  media: 5000,
 }
 
 // Sent to the parent frame so an embedder can pick a recovery without parsing

images/chromium-headful/client/tests/connect-bound.test.ts

@@ -420,4 +420,15 @@ describe('live view connect failures', () => {
 
     expect(posted).toHaveLength(1)
   })
+
+  // The stages run in sequence, so their bounds are a budget: an embedder that
+  // gives up before the last one expires never sees the reason for the stage that
+  // stalled. The watchdog in browsers/live-view.mdx is set above this sum, which
+  // is why raising a bound to 30s broke it — an embedder following that snippet
+  // remounted first and the media reason never arrived. Change one, change both.
+  test('the stage bounds fit inside the watchdog the live-view docs set', () => {
+    const budget = Object.values(CONNECT_STAGE_TIMEOUT_MS).reduce((sum, ms) => sum + ms, 0)
+
+    expect(budget).toBeLessThanOrEqual(23000)
+  })
 })