[cr141] IdentityManager shouldn't be created too early.

The upstream change was causing a crash in
BraveSpeedFeatureProcessorBrowserTest.Default browser test due to CHECK
for early creation of IdentityManager.

To avoid the check split --enable-brave-features-for-perf-testing switch
handler into two parts:
1. Changes prefs
2. Instantiates services (rewards service that causes creation of
   IdentityManager) and components.

Chromium change:

https://source.chromium.org/chromium/chromium/src/+/21435fb93f29b1ece473baf8d62d36b978fcb1a8

commit 21435fb93f29b1ece473baf8d62d36b978fcb1a8
Author: Mihai Sardarescu <msarda@chromium.org>
Date:   Tue Aug 5 03:09:57 2025 -0700

    Check that IdentityManager is not created too early

    This CL adds an explicit CHECK in the profile initialization to ensure
    that the IdentityManager is not created before the profile keyed
    services are created.

    This ensures that the IdentityManager can be properly overrides with
    a mock/fake in unit and browser tests.

    Note: This check is currently if-deffed out on Android as on this
    platform the IdentityManager is created by mistake when initializing
    the storage partition. This will be fixed in a follow-up CL.

    Bug: 436208345

browser/perf/brave_perf_features_processor.cc

@@ -53,7 +53,7 @@ void EnableAdblockCookieList(base::WeakPtr<Profile> profile) {
 
 namespace perf {
 
-void MaybeEnableBraveFeatureForPerfTesting(Profile* profile) {
+void MaybeEnableBraveFeaturesPrefsForPerfTesting(Profile* profile) {
   auto* cmd = base::CommandLine::ForCurrentProcess();
   if (!cmd->HasSwitch(switches::kEnableBraveFeaturesForPerfTesting) ||
       !cmd->HasSwitch(::switches::kUserDataDir)) {
@@ -64,11 +64,6 @@ void MaybeEnableBraveFeatureForPerfTesting(Profile* profile) {
   profile->GetPrefs()->SetBoolean(brave_ads::prefs::kOptedInToNotificationAds,
                                   true);
 
-  // Rewards
-  auto* rewards_service =
-      brave_rewards::RewardsServiceFactory::GetForProfile(profile);
-  rewards_service->CreateRewardsWallet("US", base::BindOnce(&FakeCallback));
-
   // Brave news
   profile->GetPrefs()->SetBoolean(brave_news::prefs::kNewTabPageShowToday,
                                   true);
@@ -86,6 +81,20 @@ void MaybeEnableBraveFeatureForPerfTesting(Profile* profile) {
                                base::Time::Now());
   profile->GetPrefs()->SetBoolean(
       ai_chat::prefs::kBraveChatAutocompleteProviderEnabled, true);
+}
+
+void MaybeEnableBraveFeaturesServicesAndComponentsForPerfTesting(
+    Profile* profile) {
+  auto* cmd = base::CommandLine::ForCurrentProcess();
+  if (!cmd->HasSwitch(switches::kEnableBraveFeaturesForPerfTesting) ||
+      !cmd->HasSwitch(::switches::kUserDataDir)) {
+    return;
+  }
+
+  // Rewards
+  auto* rewards_service =
+      brave_rewards::RewardsServiceFactory::GetForProfile(profile);
+  rewards_service->CreateRewardsWallet("US", base::BindOnce(&FakeCallback));
 
   // Adblock
   EnableAdblockCookieList(profile->GetWeakPtr());

browser/perf/brave_perf_features_processor.h

@@ -10,8 +10,16 @@ class Profile;
 
 namespace perf {
 
-// A handler for --enable-brave-features-for-perf-testing switch.
-void MaybeEnableBraveFeatureForPerfTesting(Profile* profile);
+// Handlers for --enable-brave-features-for-perf-testing switch.
+// They are split into two because the first is invoked from
+// BraveProfileManager::InitProfileUserPrefs and cannot instantiate services
+// that rely on identity manager because ProfileImpl::OnLocaleReady expects
+// identity manager not to be initialized before browser context services are
+// created. The second one is invoked from
+// BraveProfileManager::DoFinalInitForServices.
+void MaybeEnableBraveFeaturesPrefsForPerfTesting(Profile* profile);
+void MaybeEnableBraveFeaturesServicesAndComponentsForPerfTesting(
+    Profile* profile);
 
 }  // namespace perf
 

browser/profiles/brave_profile_manager.cc

@@ -107,8 +107,7 @@ void RecordInitialP3AValues(Profile* profile) {
 }  // namespace
 
 BraveProfileManager::BraveProfileManager(const base::FilePath& user_data_dir)
-    : ProfileManager(user_data_dir) {
-}
+    : ProfileManager(user_data_dir) {}
 
 size_t BraveProfileManager::GetNumberOfProfiles() {
   size_t count = ProfileManager::GetNumberOfProfiles();
@@ -157,7 +156,7 @@ void BraveProfileManager::InitProfileUserPrefs(Profile* profile) {
   RecordInitialP3AValues(profile);
   brave::SetDefaultSearchVersion(profile, profile->IsNewProfile());
   brave::SetDefaultThirdPartyCookieBlockValue(profile);
-  perf::MaybeEnableBraveFeatureForPerfTesting(profile);
+  perf::MaybeEnableBraveFeaturesPrefsForPerfTesting(profile);
   MigrateHttpsUpgradeSettings(profile);
 }
 
@@ -166,6 +165,7 @@ void BraveProfileManager::DoFinalInitForServices(Profile* profile,
   ProfileManager::DoFinalInitForServices(profile, go_off_the_record);
   if (!do_final_services_init_)
     return;
+  perf::MaybeEnableBraveFeaturesServicesAndComponentsForPerfTesting(profile);
   brave_ads::AdsServiceFactory::GetForProfile(profile);
   brave_rewards::RewardsServiceFactory::GetForProfile(profile);
   brave_wallet::BraveWalletServiceFactory::GetServiceForContext(profile);
@@ -230,7 +230,6 @@ void BraveProfileManager::SetNonPersonalProfilePrefs(Profile* profile) {
   prefs->SetBoolean(bookmarks::prefs::kShowBookmarkBar, false);
 }
 
-
 BraveProfileManagerWithoutInit::BraveProfileManagerWithoutInit(
     const base::FilePath& user_data_dir)
     : BraveProfileManager(user_data_dir) {