Disable prerender by default

While we are still compiling the report from the field trial, disable prerender
to be on the safer side in M61.

Bug: 678332, 735153, 520275
Change-Id: I30a2169533d30cbb85f53291223897caceddeb89
Reviewed-on: https://chromium-review.googlesource.com/584871
Commit-Queue: Egor Pasko <pasko@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491691}

chrome/browser/extensions/activity_log/activity_log_unittest.cc

@@ -21,6 +21,7 @@
 #include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
+#include "chrome/browser/prerender/prerender_test_utils.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/chrome_render_view_host_test_harness.h"
@@ -242,6 +243,9 @@ TEST_F(ActivityLogTest, LogPrerender) {
   ASSERT_TRUE(GetDatabaseEnabled());
   GURL url("http://www.google.com");
 
+  prerender::test_utils::RestorePrerenderMode restore_prerender_mode;
+  prerender::PrerenderManager::SetMode(
+      prerender::PrerenderManager::PRERENDER_MODE_ENABLED);
   prerender::PrerenderManager* prerender_manager =
       prerender::PrerenderManagerFactory::GetForBrowserContext(profile());
 

chrome/browser/predictors/autocomplete_action_predictor_unittest.cc

@@ -18,6 +18,8 @@
 #include "base/time/time.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
+#include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/prerender/prerender_test_utils.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/history/core/browser/history_service.h"
@@ -348,6 +350,9 @@ TEST_F(AutocompleteActionPredictorTest, RecommendActionURL) {
 
   AutocompleteMatch match;
   match.type = AutocompleteMatchType::HISTORY_URL;
+  prerender::test_utils::RestorePrerenderMode restore_prerender_mode;
+  prerender::PrerenderManager::SetMode(
+      prerender::PrerenderManager::PRERENDER_MODE_NOSTATE_PREFETCH);
 
   for (size_t i = 0; i < arraysize(test_url_db); ++i) {
     match.destination_url = GURL(test_url_db[i].url);
@@ -362,6 +367,9 @@ TEST_F(AutocompleteActionPredictorTest, RecommendActionSearch) {
 
   AutocompleteMatch match;
   match.type = AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED;
+  prerender::test_utils::RestorePrerenderMode restore_prerender_mode;
+  prerender::PrerenderManager::SetMode(
+      prerender::PrerenderManager::PRERENDER_MODE_NOSTATE_PREFETCH);
 
   for (size_t i = 0; i < arraysize(test_url_db); ++i) {
     match.destination_url = GURL(test_url_db[i].url);

chrome/browser/prerender/prerender_browsertest.cc

@@ -599,6 +599,10 @@ class PrerenderBrowserTest : public test_utils::PrerenderInProcessBrowserTest {
     test_utils::PrerenderInProcessBrowserTest::SetUpOnMainThread();
     prerender::PrerenderManager::SetMode(
         prerender::PrerenderManager::PRERENDER_MODE_ENABLED);
+    prerender::PrerenderManager::SetInstantMode(
+        prerender::PrerenderManager::PRERENDER_MODE_ENABLED);
+    prerender::PrerenderManager::SetOmniboxMode(
+        prerender::PrerenderManager::PRERENDER_MODE_ENABLED);
     const testing::TestInfo* const test_info =
         testing::UnitTest::GetInstance()->current_test_info();
     // This one test fails with the host resolver redirecting all hosts.

chrome/browser/prerender/prerender_field_trial.cc

@@ -71,7 +71,7 @@ const base::Feature kNoStatePrefetchFeature{"NoStatePrefetch",
 void ConfigurePrerender() {
   PrerenderManager::PrerenderManagerMode overall_mode =
       ParsePrerenderMode(kNoStatePrefetchFeatureModeParameterName,
-                         PrerenderManager::PRERENDER_MODE_ENABLED);
+                         PrerenderManager::PRERENDER_MODE_DISABLED);
 
   PrerenderManager::SetMode(overall_mode);
   PrerenderManager::SetInstantMode(ParsePrerenderMode(

chrome/browser/prerender/prerender_manager.cc

@@ -166,11 +166,11 @@ int PrerenderManager::prerenders_per_session_count_ = 0;
 
 // static
 PrerenderManager::PrerenderManagerMode PrerenderManager::mode_ =
-    PRERENDER_MODE_ENABLED;
+    PRERENDER_MODE_DISABLED;
 PrerenderManager::PrerenderManagerMode PrerenderManager::instant_mode_ =
-    PRERENDER_MODE_ENABLED;
+    PRERENDER_MODE_DISABLED;
 PrerenderManager::PrerenderManagerMode PrerenderManager::omnibox_mode_ =
-    PRERENDER_MODE_ENABLED;
+    PRERENDER_MODE_DISABLED;
 
 struct PrerenderManager::NavigationRecord {
   NavigationRecord(const GURL& url, base::TimeTicks time, Origin origin)

chrome/browser/prerender/prerender_unittest.cc

@@ -462,22 +462,16 @@ class PrerenderTest : public testing::Test {
 
 TEST_F(PrerenderTest, PrerenderRespectsDisableFlag) {
   test_utils::RestorePrerenderMode restore_prerender_mode;
-  ASSERT_TRUE(PrerenderManager::IsAnyPrerenderingPossible());
-  ASSERT_EQ(PrerenderManager::PRERENDER_MODE_ENABLED,
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndDisableFeature(kNoStatePrefetchFeature);
+  prerender::ConfigurePrerender();
+  EXPECT_FALSE(PrerenderManager::IsAnyPrerenderingPossible());
+  EXPECT_EQ(PrerenderManager::PRERENDER_MODE_DISABLED,
             PrerenderManager::GetMode(ORIGIN_NONE));
-
-  {
-    base::test::ScopedFeatureList scoped_feature_list;
-    scoped_feature_list.InitAndDisableFeature(kNoStatePrefetchFeature);
-    prerender::ConfigurePrerender();
-    EXPECT_FALSE(PrerenderManager::IsAnyPrerenderingPossible());
-    EXPECT_EQ(PrerenderManager::PRERENDER_MODE_DISABLED,
-              PrerenderManager::GetMode(ORIGIN_NONE));
-    EXPECT_EQ(PrerenderManager::PRERENDER_MODE_DISABLED,
-              PrerenderManager::GetMode(ORIGIN_OMNIBOX));
-    EXPECT_EQ(PrerenderManager::PRERENDER_MODE_DISABLED,
-              PrerenderManager::GetMode(ORIGIN_INSTANT));
-  }
+  EXPECT_EQ(PrerenderManager::PRERENDER_MODE_DISABLED,
+            PrerenderManager::GetMode(ORIGIN_OMNIBOX));
+  EXPECT_EQ(PrerenderManager::PRERENDER_MODE_DISABLED,
+            PrerenderManager::GetMode(ORIGIN_INSTANT));
 }
 
 TEST_F(PrerenderTest, PrerenderRespectsFieldTrialParameters) {
@@ -603,6 +597,7 @@ TEST_F(PrerenderTest, PrerenderRespectsFieldTrialParametersDefaultNone) {
 TEST_F(PrerenderTest, PrerenderRespectsThirdPartyCookiesPref) {
   GURL url("http://www.google.com/");
   test_utils::RestorePrerenderMode restore_prerender_mode;
+  PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_ENABLED);
   ASSERT_TRUE(PrerenderManager::IsAnyPrerenderingPossible());
 
   profile()->GetPrefs()->SetBoolean(prefs::kBlockThirdPartyCookies, true);
@@ -614,6 +609,7 @@ TEST_F(PrerenderTest, PrerenderRespectsThirdPartyCookiesPref) {
 TEST_F(PrerenderTest, OfflinePrerenderIgnoresThirdPartyCookiesPref) {
   GURL url("http://www.google.com/");
   test_utils::RestorePrerenderMode restore_prerender_mode;
+  PrerenderManager::SetMode(PrerenderManager::PRERENDER_MODE_ENABLED);
   ASSERT_TRUE(PrerenderManager::IsAnyPrerenderingPossible());
 
   profile()->GetPrefs()->SetBoolean(prefs::kBlockThirdPartyCookies, true);
@@ -715,6 +711,7 @@ TEST_F(PrerenderTest, OfflinePrerenderIgnoresPrerenderMode) {
 
 TEST_F(PrerenderTest, PrerenderDisabledOnLowEndDevice) {
   GURL url("http://www.google.com/");
+  prerender_manager()->SetMode(PrerenderManager::PRERENDER_MODE_ENABLED);
   ASSERT_TRUE(PrerenderManager::IsAnyPrerenderingPossible());
   prerender_manager()->SetIsLowEndDevice(true);
   EXPECT_FALSE(AddSimplePrerender(url));
@@ -724,6 +721,7 @@ TEST_F(PrerenderTest, PrerenderDisabledOnLowEndDevice) {
 
 TEST_F(PrerenderTest, OfflinePrerenderPossibleOnLowEndDevice) {
   GURL url("http://www.google.com/");
+  prerender_manager()->SetMode(PrerenderManager::PRERENDER_MODE_ENABLED);
   ASSERT_TRUE(PrerenderManager::IsAnyPrerenderingPossible());
 
   prerender_manager()->SetIsLowEndDevice(true);
@@ -1393,6 +1391,8 @@ TEST_F(PrerenderTest, CancelAllTest) {
 
 TEST_F(PrerenderTest, OmniboxNotAllowedWhenDisabled) {
   DisablePrerender();
+  test_utils::RestorePrerenderMode restore_prerender_mode;
+  PrerenderManager::SetOmniboxMode(PrerenderManager::PRERENDER_MODE_ENABLED);
   EXPECT_FALSE(prerender_manager()->AddPrerenderFromOmnibox(
       GURL("http://www.example.com"), nullptr, gfx::Size()));
   histogram_tester().ExpectUniqueSample("Prerender.FinalStatus",

chrome/browser/ui/search/instant_search_prerenderer_unittest.cc

@@ -22,6 +22,7 @@
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/prerender/prerender_origin.h"
 #include "chrome/browser/prerender/prerender_tab_helper.h"
+#include "chrome/browser/prerender/prerender_test_utils.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/instant_service.h"
 #include "chrome/browser/search/instant_unittest_base.h"
@@ -187,12 +188,25 @@ class InstantSearchPrerendererTest : public InstantUnitTestBase {
   InstantSearchPrerendererTest() {}
 
  protected:
+  using RestorePrerenderMode = prerender::test_utils::RestorePrerenderMode;
+
   void SetUp() override {
     ASSERT_TRUE(base::FieldTrialList::CreateFieldTrial("EmbeddedSearch",
                                                        "Group1 strk:20"));
+
+    // Prerender mode is stored in a few static variables. Remember the default
+    // mode to restore it later in TearDown() to avoid affecting other tests.
+    restore_prerender_mode_ = base::MakeUnique<RestorePrerenderMode>();
+    PrerenderManager::SetInstantMode(PrerenderManager::PRERENDER_MODE_ENABLED);
+
     InstantUnitTestBase::SetUp();
   }
 
+  void TearDown() override {
+    InstantUnitTestBase::TearDown();
+    restore_prerender_mode_.reset();
+  }
+
   void Init(bool prerender_search_results_base_page,
             bool call_did_finish_load) {
     AddTab(browser(), GURL(url::kAboutBlankURL));
@@ -250,6 +264,7 @@ class InstantSearchPrerendererTest : public InstantUnitTestBase {
 
  private:
   MockEmbeddedSearchClient mock_embedded_search_client_;
+  std::unique_ptr<RestorePrerenderMode> restore_prerender_mode_;
 };
 
 TEST_F(InstantSearchPrerendererTest, GetSearchTermsFromPrerenderedPage) {