Split PSS sign-out unit tests and fix StopAndClear misconception

This CL has 2 goals.

1) Split EnableSyncSignOutAndChangeAccount into smaller tests so that
when the linked bug is fixed, we have a good place to put our
expectation that IsSyncRequested gets cleared on sign-out. The existing
test apparently was even testing some invalidations code [1].

2) Stop coupling StopAndClear() with sign-out in documentation/comments,
since this isn't super true nowadays. For example on Desktop, when the
user chooses to disable sync by sign-out + clear all data, the
StopAndClear() call is rather a by-product of deleting the profile [2],
not of clearing the primary account on the identity manager.

As a bonus, we update some references in comments to RequestStop(), the
old name of StopAndClear().

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1164954/52/components/browser_sync/profile_sync_service_unittest.cc#707
[2] https://source.chromium.org/chromium/chromium/src/+/a5edbb26dc14b07795e7c45fa15998a4dc7f7fad:chrome/browser/ui/webui/settings/people_handler.cc;l=706

Bug: 1147026
Change-Id: I1d9dc5af66a7e58a52d6cf0f3942db315926acfd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2530029
Commit-Queue: Victor Vianna <victorvianna@google.com>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826227}

chrome/browser/sync/test/integration/enable_disable_test.cc

@@ -350,10 +350,10 @@ IN_PROC_BROWSER_TEST_F(EnableDisableSingleClientTest, FastEnableDisableEnable) {
   }
 }
 
-// This test makes sure that after a RequestStop(CLEAR_DATA), Sync data gets
-// redownloaded when Sync is started again. This does not actually verify that
-// the data is gone from disk (which seems infeasible); it's mostly here as a
-// baseline for the following tests.
+// This test makes sure that after a StopAndClear(), Sync data gets redownloaded
+// when Sync is started again. This does not actually verify that the data is
+// gone from disk (which seems infeasible); it's mostly here as a baseline for
+// the following tests.
 IN_PROC_BROWSER_TEST_F(EnableDisableSingleClientTest,
                        RedownloadsAfterClearData) {
   ASSERT_TRUE(SetupClients());

components/sync/driver/profile_sync_service.h

@@ -319,9 +319,10 @@ class ProfileSyncService : public SyncService,
                                 const std::string& message,
                                 UnrecoverableErrorReason reason);
 
-  // Stops the sync engine. Does NOT set IsSyncRequested to false. Use
-  // RequestStop for that. |data_fate| controls whether the local sync data is
+  // Stops the sync engine. |data_fate| controls whether the local sync data is
   // deleted or kept when the engine shuts down.
+  // Does NOT set IsSyncRequested to false, use StopAndClear() or
+  // SyncUserSettings::SetSyncRequested() for that.
   void StopImpl(SyncStopDataFate data_fate);
 
   // Puts the engine's sync scheduler into NORMAL mode.

components/sync/driver/profile_sync_service_unittest.cc

@@ -648,36 +648,81 @@ TEST_F(ProfileSyncServiceTest, DisableAndEnableSyncTemporarily) {
 }
 
 // Certain ProfileSyncService tests don't apply to Chrome OS, for example
-// things that deal with concepts like "signing out" and policy.
+// things that deal with concepts like "signing out".
 #if !defined(OS_CHROMEOS)
-TEST_F(ProfileSyncServiceTest, EnableSyncSignOutAndChangeAccount) {
+TEST_F(ProfileSyncServiceTest, SignOutDisablesSyncTransportAndSyncFeature) {
+  // Sign-in and enable sync.
   CreateService(ProfileSyncService::AUTO_START);
   SignIn();
   InitializeForNthSync();
-
-  EXPECT_EQ(SyncService::DisableReasonSet(), service()->GetDisableReasons());
-  EXPECT_EQ(SyncService::TransportState::ACTIVE,
+  ASSERT_EQ(SyncService::DisableReasonSet(), service()->GetDisableReasons());
+  ASSERT_EQ(SyncService::TransportState::ACTIVE,
             service()->GetTransportState());
-  EXPECT_EQ(identity_manager()->GetPrimaryAccountId(),
-            identity_provider()->GetActiveAccountId());
 
+  // Sign-out.
   auto* account_mutator = identity_manager()->GetPrimaryAccountMutator();
-
-  // GetPrimaryAccountMutator() returns nullptr on ChromeOS only.
-  DCHECK(account_mutator);
+  DCHECK(account_mutator) << "Account mutator should only be null on ChromeOS.";
   account_mutator->ClearPrimaryAccount(
       signin::PrimaryAccountMutator::ClearAccountsAction::kDefault,
       signin_metrics::SIGNOUT_TEST,
       signin_metrics::SignoutDelete::IGNORE_METRIC);
-  // Wait for PSS to be notified that the primary account has gone away.
+  // Wait for ProfileSyncService to be notified.
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(
       SyncService::DisableReasonSet(SyncService::DISABLE_REASON_NOT_SIGNED_IN),
       service()->GetDisableReasons());
   EXPECT_EQ(SyncService::TransportState::DISABLED,
             service()->GetTransportState());
+}
+
+TEST_F(ProfileSyncServiceTest,
+       SignOutClearsSyncTransportDataAndSyncTheFeaturePrefs) {
+  // Sign-in and enable sync.
+  CreateService(ProfileSyncService::AUTO_START);
+  SignIn();
+  InitializeForNthSync();
+  ASSERT_TRUE(service()->GetUserSettings()->IsFirstSetupComplete());
+  ASSERT_TRUE(service()->GetUserSettings()->IsSyncRequested());
+
+  // Sign-out.
+  auto* account_mutator = identity_manager()->GetPrimaryAccountMutator();
+  DCHECK(account_mutator) << "Account mutator should only be null on ChromeOS.";
+  EXPECT_CALL(*sync_client(), OnLocalSyncTransportDataCleared())
+      .Times(testing::AtLeast(1));
+  account_mutator->ClearPrimaryAccount(
+      signin::PrimaryAccountMutator::ClearAccountsAction::kDefault,
+      signin_metrics::SIGNOUT_TEST,
+      signin_metrics::SignoutDelete::IGNORE_METRIC);
+  // Wait for ProfileSyncService to be notified.
+  base::RunLoop().RunUntilIdle();
+  // These are specific to sync-the-feature and should be cleared.
+  EXPECT_FALSE(service()->GetUserSettings()->IsFirstSetupComplete());
+  // TODO(crbug.com/1147026): Add expectation for IsSyncRequested when it's
+  // being cleared.
+}
+
+TEST_F(ProfileSyncServiceTest, IdentityProvider_GetActiveAccountId) {
+  // Sign-in and enable sync.
+  CreateService(ProfileSyncService::AUTO_START);
+  SignIn();
+  InitializeForNthSync();
+  EXPECT_EQ(identity_manager()->GetPrimaryAccountId(),
+            identity_provider()->GetActiveAccountId());
+
+  // Sign out.
+  auto* account_mutator = identity_manager()->GetPrimaryAccountMutator();
+  DCHECK(account_mutator) << "Account mutator should only be null on ChromeOS.";
+  account_mutator->ClearPrimaryAccount(
+      signin::PrimaryAccountMutator::ClearAccountsAction::kDefault,
+      signin_metrics::SIGNOUT_TEST,
+      signin_metrics::SignoutDelete::IGNORE_METRIC);
+  // Wait for ProfileSyncService to be notified.
+  base::RunLoop().RunUntilIdle();
+
+  // The identity provider should show no active account.
   EXPECT_EQ(CoreAccountId(), identity_provider()->GetActiveAccountId());
 
+  // Change account.
   identity_test_env()->MakePrimaryAccountAvailable("new_user@gmail.com");
   EXPECT_EQ(identity_manager()->GetPrimaryAccountId(),
             identity_provider()->GetActiveAccountId());
@@ -938,8 +983,8 @@ TEST_F(ProfileSyncServiceTest, SignOutRevokeAccessToken) {
 }
 #endif
 
-// Verify that prefs are cleared on sign-out.
-TEST_F(ProfileSyncServiceTest, ClearDataOnSignOut) {
+TEST_F(ProfileSyncServiceTest,
+       StopAndClearWillClearDataAndSwitchToTransportMode) {
   SignIn();
   CreateService(ProfileSyncService::AUTO_START);
   InitializeForNthSync();
@@ -949,15 +994,14 @@ TEST_F(ProfileSyncServiceTest, ClearDataOnSignOut) {
   ASSERT_LT(base::Time::Now() - last_synced_time,
             base::TimeDelta::FromMinutes(1));
 
-  // Local transport data should be cleared and the client notified.
   EXPECT_CALL(*sync_client(), OnLocalSyncTransportDataCleared())
       .Times(testing::AtLeast(1));
 
-  // Sign out.
   service()->StopAndClear();
 
-  // Even though Sync-the-feature is disabled, Sync-the-transport should still
-  // be running, and should have updated the last synced time.
+  // Even though Sync-the-feature is disabled, there's still an (unconsented)
+  // signed-in account, so Sync-the-transport should still be running and
+  // should have updated the last synced time.
   EXPECT_EQ(SyncService::TransportState::ACTIVE,
             service()->GetTransportState());
   EXPECT_FALSE(service()->IsSyncFeatureEnabled());
@@ -978,7 +1022,7 @@ TEST_F(ProfileSyncServiceTest, ClearDemographicsOnInitializeWhenSignedOut) {
   InitializeForNthSync();
 }
 
-TEST_F(ProfileSyncServiceTest, CancelSyncAfterSignOut) {
+TEST_F(ProfileSyncServiceTest, StopSyncAndClearTwiceDoesNotCrash) {
   SignIn();
   CreateService(ProfileSyncService::AUTO_START);
   InitializeForNthSync();

components/sync/driver/resources/chrome_sync.js

@@ -104,14 +104,14 @@ cr.define('chrome.sync', function() {
   }
 
   /**
-   * Triggers a RequestStop(KEEP_DATA) call on the SyncService.
+   * Stops the SyncService while keeping the sync data around.
    */
   function requestStopKeepData() {
     chrome.send('requestStopKeepData');
   }
 
   /**
-   * Triggers a RequestStop(CLEAR_DATA) call on the SyncService.
+   * Stops the SyncService and clears the sync data.
    */
   function requestStopClearData() {
     chrome.send('requestStopClearData');

components/sync/driver/sync_service.h

@@ -319,10 +319,8 @@ class SyncService : public KeyedService {
   // ACTIONS / STATE CHANGE REQUESTS
   //////////////////////////////////////////////////////////////////////////////
 
-  // Stops sync and clears all local data. This usually gets called when the
-  // user fully signs out (i.e. removes the primary account).
-  // Note: This refers to Sync-the-feature. Sync-the-transport may remain active
-  // after calling this.
+  // Stops sync-the-feature and clears all local data. Sync-the-transport may
+  // remain active after calling this.
   virtual void StopAndClear() = 0;
 
   // Called when a datatype (SyncableService) has a need for sync to start