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Prerender: Add timer logic for DSE Prerender
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To ensure prerendered results are fresh, this CL deletes the unused
prerendered search results after a fixed duration(following search
prefetch setting).

It also adds a metric tracking the duration between:
1. chrome receives the first correct prerender hints
2. user navigates to the search result page.

Besides that, this CL is the first step to make prerender reuse the
prefetched response. See ryansturm@'s comments on the second patchset in
this CL https://crrev.com/c/3459941. So the newly added metric would
also be used to find the best threshold.

This change should not affect the DSE's PrerenderPredictionStatus.
The newly added SearchPrerenderTask plays the role that
search_prerender_handle_ played before this CL. It is responsible for
tracking a started search prerender, and it keeps alive even if the
handle_ is destroyed by the timer. With its help, PrerenderManager can
record the prediction regardless whether a prerender is expired or not.


Bug: 1295170, 1278634
Change-Id: Ie52c245b752d64e1139627579dcd62700aedebed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3495266
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Angela Yoeurng <yoangela@chromium.org>
Reviewed-by: Asami Doi <asamidoi@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Lingqi Chi <lingqi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#984254}
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@Clqsin45
Clqsin45 authored and Chromium LUCI CQ committed Mar 23, 2022
1 parent 8802b00 commit c5014c3
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Showing 7 changed files with 483 additions and 87 deletions.
3 changes: 2 additions & 1 deletion chrome/browser/android/omnibox/autocomplete_controller_android.cc
View file
Expand Up @@ -366,7 +366,8 @@ void AutocompleteControllerAndroid::OnSuggestionSelected(
// PrerenderManager.
if (web_contents) {
auto* prerender_manager = PrerenderManager::FromWebContents(web_contents);
if (!prerender_manager || !prerender_manager->search_prerender_handle()) {
if (!prerender_manager ||
!prerender_manager->HasSearchResultPagePrerendered()) {
base::UmaHistogramEnumeration(
internal::kHistogramPrerenderPredictionStatusDefaultSearchEngine,
PrerenderPredictionStatus::kNotStarted);
Expand Down
202 changes: 202 additions & 0 deletions chrome/browser/prerender/omnibox_prerender_browsertest.cc
View file
Expand Up @@ -11,20 +11,29 @@
#include "chrome/browser/predictors/autocomplete_action_predictor.h"
#include "chrome/browser/predictors/autocomplete_action_predictor_factory.h"
#include "chrome/browser/prefetch/prefetch_prefs.h"
#include "chrome/browser/prefetch/search_prefetch/field_trial_settings.h"
#include "chrome/browser/prerender/prerender_manager.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/search_engines/template_url_service_factory.h"
#include "chrome/common/chrome_features.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/pref_names.h"
#include "chrome/test/base/chrome_test_utils.h"
#include "chrome/test/base/search_test_utils.h"
#include "chrome/test/base/testing_profile.h"
#include "components/omnibox/browser/autocomplete_match.h"
#include "components/policy/policy_constants.h"
#include "components/prefs/pref_service.h"
#include "components/search_engines/template_url_data.h"
#include "components/search_engines/template_url_service.h"
#include "content/public/test/browser_test.h"
#include "content/public/test/browser_test_utils.h"
#include "content/public/test/prerender_test_util.h"
#include "content/public/test/test_navigation_observer.h"
#include "net/dns/mock_host_resolver.h"
#include "net/test/embedded_test_server/embedded_test_server.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "ui/base/page_transition_types.h"

#if BUILDFLAG(IS_ANDROID)
#include "chrome/test/base/android/android_browser_test.h"
Expand Down Expand Up @@ -232,4 +241,197 @@ IN_PROC_BROWSER_TEST_F(OmniboxPrerenderDefaultPrerender2BrowserTest,
#endif
}

class PrerenderOmniboxSearchSuggestionExpiryBrowserTest
: public OmniboxPrerenderBrowserTest {
public:
PrerenderOmniboxSearchSuggestionExpiryBrowserTest() {
feature_list_.InitWithFeaturesAndParameters(
{{features::kSupportSearchSuggestionForPrerender2, {}},
{kSearchPrefetchServicePrefetching,
{
{"prefetch_caching_limit_ms", "10"},
}}},
{});
}

void SetUpOnMainThread() override {
OmniboxPrerenderBrowserTest::SetUpOnMainThread();
host_resolver()->AddRule("*", "127.0.0.1");

search_engine_server_.SetSSLConfig(
net::test_server::EmbeddedTestServer::CERT_TEST_NAMES);
search_engine_server_.ServeFilesFromDirectory(
base::PathService::CheckedGet(chrome::DIR_TEST_DATA));
ASSERT_TRUE(search_engine_server_.Start());

TemplateURLService* model = TemplateURLServiceFactory::GetForProfile(
chrome_test_utils::GetProfile(this));
ASSERT_TRUE(model);
search_test_utils::WaitForTemplateURLServiceToLoad(model);
ASSERT_TRUE(model->loaded());
TemplateURLData data;
data.SetShortName(kSearchDomain16);
data.SetKeyword(data.short_name());
data.SetURL(search_engine_server_
.GetURL(kSearchDomain, "/title1.html?q={searchTerms}")
.spec());
TemplateURL* template_url = model->Add(std::make_unique<TemplateURL>(data));
ASSERT_TRUE(template_url);
model->SetUserSelectedDefaultSearchProvider(template_url);
}

protected:
int PrerenderQuery(const std::string& search_terms,
const GURL& expected_prerender_url) {
AutocompleteMatch match = CreateSearchSuggestionMatch(search_terms);
prerender_manager_->StartPrerenderSearchSuggestion(match);
int host_id = prerender_helper().GetHostForUrl(expected_prerender_url);
EXPECT_NE(host_id, content::RenderFrameHost::kNoFrameTreeNodeId);
return host_id;
}

void PrerenderQueryAndWaitForExpiring(const std::string& search_terms,
const GURL& expected_prerender_url) {
int host_id = PrerenderQuery(search_terms, expected_prerender_url);

content::test::PrerenderHostObserver prerender_observer(
*GetActiveWebContents(), host_id);

// The prerender will be destroyed automatically soon, since the duration is
// set to 10ms.
prerender_observer.WaitForDestroyed();
}

GURL GetSearchSuggestionUrl(const std::string& search_terms) {
return search_engine_server_.GetURL(kSearchDomain,
"/title1.html?q=" + search_terms);
}

void InitializePrerenderManager() {
PrerenderManager::CreateForWebContents(GetActiveWebContents());

prerender_manager_ =
PrerenderManager::FromWebContents(GetActiveWebContents());
ASSERT_TRUE(prerender_manager_);
}

PrerenderManager* prerender_manager() { return prerender_manager_; }

private:
AutocompleteMatch CreateSearchSuggestionMatch(
const std::string& search_terms) {
AutocompleteMatch match;
match.search_terms_args = std::make_unique<TemplateURLRef::SearchTermsArgs>(
base::UTF8ToUTF16(search_terms));
match.search_terms_args->original_query = base::UTF8ToUTF16(search_terms);
match.destination_url = GetSearchSuggestionUrl(search_terms);
match.keyword = base::UTF8ToUTF16(search_terms);
match.RecordAdditionalInfo("should_prerender", "true");
return match;
}

constexpr static char kSearchDomain[] = "a.test";
constexpr static char16_t kSearchDomain16[] = u"a.test";
base::test::ScopedFeatureList feature_list_;
PrerenderManager* prerender_manager_;
net::test_server::EmbeddedTestServer search_engine_server_{
net::test_server::EmbeddedTestServer::TYPE_HTTPS};
};

// Tests that an ongoing prerender which loads an SRP should be canceled
// automatically after the expiry duration.
IN_PROC_BROWSER_TEST_F(PrerenderOmniboxSearchSuggestionExpiryBrowserTest,
SearchPrerenderExpiry) {
base::HistogramTester histogram_tester;
const GURL kInitialUrl = embedded_test_server()->GetURL("/empty.html");
ASSERT_TRUE(GetActiveWebContents());
ASSERT_TRUE(content::NavigateToURL(GetActiveWebContents(), kInitialUrl));
InitializePrerenderManager();

std::string search_query = "prerender2";
GURL expected_prerender_url = GetSearchSuggestionUrl("prerender222");
PrerenderQueryAndWaitForExpiring("prerender222", expected_prerender_url);

histogram_tester.ExpectUniqueSample(
"Prerender.Experimental.PrerenderHostFinalStatus.Embedder_"
"DefaultSearchEngine",
/*PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed*/ 35, 1);

// Select the prerender hint. The prerendered result has been deleted, so
// browser loads the search result over again.
content::TestNavigationObserver observer(GetActiveWebContents());
GetActiveWebContents()->OpenURL(content::OpenURLParams(
expected_prerender_url, content::Referrer(),
WindowOpenDisposition::CURRENT_TAB,
ui::PageTransitionFromInt(ui::PAGE_TRANSITION_GENERATED |
ui::PAGE_TRANSITION_FROM_ADDRESS_BAR),
/*is_renderer_initiated=*/false));
observer.Wait();

// The prediction is correct, so kHitFinished should be recorded.
histogram_tester.ExpectUniqueSample(
internal::kHistogramPrerenderPredictionStatusDefaultSearchEngine,
PrerenderPredictionStatus::kHitFinished, 1);
// Since the prerendered page ran out of time, the timing metric should
// record `prefetch_caching_limit_ms`.
histogram_tester.ExpectUniqueTimeSample(
"Prerender.Experimental.Search."
"FirstCorrectPrerenderHintReceivedToRealSearchNavigationStartedDuration",
base::Milliseconds(10), 1);
}

// Tests that kCanceled is correctly recorded in the case that PrerenderManager
// receives a new suggestion. Note: kCancel should only recorded when
// PrerenderManager receives a new suggestion or on primary-page changed.
// Otherwise one prediction might be recorded twice.
IN_PROC_BROWSER_TEST_F(PrerenderOmniboxSearchSuggestionExpiryBrowserTest,
DifferentSuggestionAfterPrerenderExpired) {
base::HistogramTester histogram_tester;
const GURL kInitialUrl = embedded_test_server()->GetURL("/empty.html");
ASSERT_TRUE(GetActiveWebContents());
ASSERT_TRUE(content::NavigateToURL(GetActiveWebContents(), kInitialUrl));
InitializePrerenderManager();

GURL expected_prerender_url = GetSearchSuggestionUrl("prerender222");
// Prerender the first query, and wait for it to be deleted.
PrerenderQueryAndWaitForExpiring("prerender222", expected_prerender_url);

histogram_tester.ExpectUniqueSample(
"Prerender.Experimental.PrerenderHostFinalStatus.Embedder_"
"DefaultSearchEngine",
/*PrerenderHost::FinalStatus::kEmbedderTriggeredAndDestroyed*/ 35, 1);

// Nothing should be recorded. Because there is no new navigation nor new
// search suggestion.
histogram_tester.ExpectTotalCount(
internal::kHistogramPrerenderPredictionStatusDefaultSearchEngine, 0);

// Suggest to prerender another term.
GURL prerender_url_2 = GetSearchSuggestionUrl("prerender233");
PrerenderQuery("prerender233", prerender_url_2);

// PrerenderPredictionStatus::kCancelled should be recorded for the prediction
// of "prerender222".
histogram_tester.ExpectUniqueSample(
internal::kHistogramPrerenderPredictionStatusDefaultSearchEngine,
PrerenderPredictionStatus::kCancelled, 1);

content::TestNavigationObserver observer(GetActiveWebContents());
GetActiveWebContents()->OpenURL(content::OpenURLParams(
prerender_url_2, content::Referrer(), WindowOpenDisposition::CURRENT_TAB,
ui::PageTransitionFromInt(ui::PAGE_TRANSITION_GENERATED |
ui::PAGE_TRANSITION_FROM_ADDRESS_BAR),
/*is_renderer_initiated=*/false));
observer.Wait();

// The prediction is correct, so kHitFinished should be recorded.
histogram_tester.ExpectBucketCount(
internal::kHistogramPrerenderPredictionStatusDefaultSearchEngine,
PrerenderPredictionStatus::kHitFinished, 1);

// Two predictions, two samples.
histogram_tester.ExpectTotalCount(
internal::kHistogramPrerenderPredictionStatusDefaultSearchEngine, 2);
}

} // namespace

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