view-transition: Fix bugs with pre-render integration.

This change fixes the following issues for ViewTransition + pre-render:

1. Explicitly track when we're running commit deferring conditions for
a pre-render. This is to allow using the tentative origin for
same-origin checks.

2. If the pre-render is cancelled after running commit deferring
conditions, disable ViewTransition for this navigation.

Finally add an assert to ensure that if we're sending the ViewTransition
state, the navigation *must* be same-origin.

Fixed: 326265171
Change-Id: I8b0e901318426f3e696e9f43a14921e985fe1cca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5329047
Commit-Queue: Khushal Sagar <[email protected]>
Auto-Submit: Khushal Sagar <[email protected]>
Reviewed-by: David Bokan <[email protected]>
Reviewed-by: Rakina Zata Amni <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1266420}

speculation-rules/prerender/resources/utils.js

@@ -15,6 +15,7 @@ function startPrerendering(url, rule_extras = {}) {
   script.text = JSON.stringify(
       {prerender: [{source: 'list', urls: [url], ...rule_extras}]});
   document.head.appendChild(script);
+  return script;
 }
 
 class PrerenderChannel extends EventTarget {