Init PromosManager from IOSChromeMainParts.

This change ensures the new Fullscreen Promos Manager is initialized in
IOSChromeMainParts.

Bug: 1349067
Change-Id: I57cb79570f67b0e51a2be8f6c06e04f9ce8e6119
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3798776
Reviewed-by: Guillaume Jenkins <gujen@google.com>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Benjamin Williams <bwwilliams@google.com>
Cr-Commit-Position: refs/heads/main@{#1032753}

ios/chrome/browser/ios_chrome_main_parts.mm

@@ -61,6 +61,7 @@
 #include "ios/chrome/browser/open_from_clipboard/create_clipboard_recent_content.h"
 #include "ios/chrome/browser/policy/browser_policy_connector_ios.h"
 #include "ios/chrome/browser/pref_names.h"
+#import "ios/chrome/browser/promos_manager/promos_manager.h"
 #import "ios/chrome/browser/safe_browsing/safe_browsing_metrics_collector_factory.h"
 #import "ios/chrome/browser/signin/signin_util.h"
 #include "ios/chrome/browser/translate/chrome_ios_translate_client.h"
@@ -398,6 +399,10 @@ void IOSChromeMainParts::PreMainMessageLoopRun() {
 
   // Set monitoring for some experimental flags.
   MonitorExperimentalSettingsChanges();
+
+  // Ensure the Fullscren Promos Manager is initialized.
+  PromosManager* promos_manager = application_context_->GetPromosManager();
+  promos_manager->Init();
 }
 
 void IOSChromeMainParts::PostMainMessageLoopRun() {

ios/chrome/browser/promos_manager/promos_manager.mm

@@ -10,6 +10,7 @@
 #import "base/values.h"
 #import "components/prefs/pref_service.h"
 #import "ios/chrome/browser/pref_names.h"
+#import "ios/chrome/browser/promos_manager/features.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -28,6 +29,9 @@ PromosManager::~PromosManager() = default;
 #pragma mark - Public methods
 
 void PromosManager::Init() {
+  if (!IsFullscreenPromosManagerEnabled())
+    return;
+
   DCHECK(local_state_);
 
   const base::Value::List& stored_active_promos =