fix: move FirstPartySets into the browser process (electron#33998)

Ref: https://chromium-review.googlesource.com/c/chromium/src/+/3448551

shell/browser/electron_browser_main_parts.cc

@@ -25,6 +25,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/device_service.h"
+#include "content/public/browser/first_party_sets_handler.h"
 #include "content/public/browser/web_ui_controller_factory.h"
 #include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
@@ -416,6 +417,11 @@ int ElectronBrowserMainParts::PreMainMessageLoopRun() {
   // url::Add*Scheme are not threadsafe, this helps prevent data races.
   url::LockSchemeRegistries();
 
+  // The First-Party Sets feature always expects to be initialized
+  // CL: https://chromium-review.googlesource.com/c/chromium/src/+/3448551
+  content::FirstPartySetsHandler::GetInstance()->SetPublicFirstPartySets(
+      base::File());
+
 #if BUILDFLAG(ENABLE_ELECTRON_EXTENSIONS)
   extensions_client_ = std::make_unique<ElectronExtensionsClient>();
   extensions::ExtensionsClient::Set(extensions_client_.get());

shell/browser/net/system_network_context_manager.cc

@@ -20,7 +20,6 @@
 #include "components/os_crypt/os_crypt.h"
 #include "components/prefs/pref_service.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/first_party_sets_handler.h"
 #include "content/public/browser/network_service_instance.h"
 #include "content/public/common/content_features.h"
 #include "content/public/common/network_service_util.h"
@@ -289,11 +288,6 @@ void SystemNetworkContextManager::OnNetworkServiceCreated(
       base::FeatureList::IsEnabled(features::kAsyncDns),
       default_secure_dns_mode, doh_config, additional_dns_query_types_enabled);
 
-  // Initializes first party sets component
-  // CL: https://chromium-review.googlesource.com/c/chromium/src/+/3449280
-  content::FirstPartySetsHandler::GetInstance()->SetPublicFirstPartySets(
-      base::File());
-
   std::string app_name = electron::Browser::Get()->GetName();
 #if BUILDFLAG(IS_MAC)
   KeychainPassword::GetServiceName() = app_name + " Safe Storage";