Prerender: allow same-origin main frame navigations

Allowing main frame navigations in a prerendered page (crbug.com/1239281) is being implemented in 2 CLs and this CL is one
of them:
1. Allow same-origin navigations in a prerendered page. <-- this CL
2. Allow same-site navigations in a prerendered page. (https://chromium-review.googlesource.com/c/chromium/src/+/4040627)

design docs: https://docs.google.com/document/d/1fq3ywTnDee1bKPlWleyRVcW3vEvKIug5m_7r4p5NcbI/edit?usp=sharing&resourcekey=0-LAwzE7wJODURIJA5ewAj_g

Bug: 1239281
Change-Id: Ia5329fe6be5cc4ea6bcb1c74ca73602099526aee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3970286
Commit-Queue: Asami Doi <asamidoi@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Lingqi Chi <lingqi@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1099094}

chrome/browser/preloading/prefetch/search_prefetch/search_preload_unified_browsertest.cc

@@ -1512,12 +1512,13 @@ IN_PROC_BROWSER_TEST_F(SearchPreloadUnifiedBrowserTest,
       "Omnibox.SearchPrefetch.PrefetchServingReason2.Prerender",
       SearchPrefetchServingReason::kPrerendered, 1);
 
-  // 4. Fail the prerender by navigating it to another page.
+  // 4. Fail the prerender by navigating it to a cross-site page.
   content::test::PrerenderHostObserver prerender_observer(
       *GetActiveWebContents(), expected_prerender_url);
   int host_id = prerender_helper().GetHostForUrl(expected_prerender_url);
   ASSERT_NE(host_id, content::RenderFrameHost::kNoFrameTreeNodeId);
-  prerender_helper().NavigatePrerenderedPage(host_id, expected_prefetch_url);
+  prerender_helper().NavigatePrerenderedPage(
+      host_id, embedded_test_server()->GetURL("a.com", "/title1.html"));
   prerender_observer.WaitForDestroyed();
   EXPECT_EQ(1, prerender_helper().GetRequestCount(expected_prefetch_url));
   EXPECT_EQ(0, prerender_helper().GetRequestCount(expected_prerender_url));

chrome/browser/subresource_filter/subresource_filter_prerender_browsertest.cc

@@ -309,7 +309,8 @@ IN_PROC_BROWSER_TEST_F(SubresourceFilterPrerenderingBrowserTest,
 IN_PROC_BROWSER_TEST_F(SubresourceFilterPrerenderingBrowserTest,
                        NavigatePrerenderedPage) {
   const GURL kPrerenderUrl1 = embedded_test_server()->GetURL("/title1.html");
-  const GURL kPrerenderUrl2 = embedded_test_server()->GetURL("/title2.html");
+  const GURL kPrerenderUrl2 =
+      embedded_test_server()->GetURL("a.com", "/title2.html");
   const GURL kInitialUrl = embedded_test_server()->GetURL("/empty.html");
 
   // Navigate to the initial URL.
@@ -318,8 +319,8 @@ IN_PROC_BROWSER_TEST_F(SubresourceFilterPrerenderingBrowserTest,
   // Trigger a prerendering of title1.html.
   const int prerender_host_id = prerender_helper_.AddPrerender(kPrerenderUrl1);
 
-  // Now navigate the prerendered page to title2.html. Ensure the prerender is
-  // canceled.
+  // Now navigate the prerendered page to a cross-site page. Ensure the
+  // prerender is canceled.
   // TODO(bokan): If this is ever changed, we should ensure this test checks
   // that we navigate the prerender between filtered and unfiltered pages, and
   // ensure subresources are correctly filtered (or not).

content/browser/devtools/protocol/page_handler.cc

@@ -1599,6 +1599,8 @@ Page::PrerenderFinalStatus PrerenderFinalStatusToProtocol(
       return Page::PrerenderFinalStatusEnum::PreloadingDisabled;
     case PrerenderFinalStatus::kBatterySaverEnabled:
       return Page::PrerenderFinalStatusEnum::BatterySaverEnabled;
+    case PrerenderFinalStatus::kActivatedDuringMainFrameNavigation:
+      return Page::PrerenderFinalStatusEnum::ActivatedDuringMainFrameNavigation;
   }
 }
 

content/browser/preloading/preloading_attempt_impl.cc

@@ -42,8 +42,11 @@ void DCHECKTriggeringOutcomeTransitions(PreloadingTriggeringOutcome old_state,
           // It can be possible that the preloading attempt may end up failing
           // after being ready to use, for cases where we have to cancel the
           // attempt for performance and security reasons.
+          // The transition of kReady to kReady occurs when the main frame
+          // navigation is completed in a preloaded page.
           {PreloadingTriggeringOutcome::kReady,
-           {PreloadingTriggeringOutcome::kSuccess,
+           {PreloadingTriggeringOutcome::kReady,
+            PreloadingTriggeringOutcome::kSuccess,
             PreloadingTriggeringOutcome::kFailure,
             PreloadingTriggeringOutcome::kTriggeredButUpgradedToPrerender}},