Adopt base::NoDestructor for KeyedService factories

For changes under /chrome/browser/privacy_sandbox

It replaces base::Singleton, following the latest recommendation
in base/ and browser_context_keyed_service_factory.h.

For factories with a trivial destructor, it makes no difference.

LSC doc:
https://docs.google.com/document/d/1x1LqRQyfBOmpMkNQBYs7QBPSxLtuiImvmgcJYI_kaS4/edit?usp=sharing

This CL was uploaded by git cl split.

R=rainhard@chromium.org

Bug: 925323
Change-Id: I6d51c8fbd37928409138127385aef57d3ce4c1dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4573565
Reviewed-by: Rainhard Findling <rainhard@chromium.org>
Commit-Queue: Rainhard Findling <rainhard@chromium.org>
Auto-Submit: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1150444}

chrome/browser/privacy_sandbox/privacy_sandbox_service_factory.cc

@@ -4,7 +4,7 @@
 
 #include "chrome/browser/privacy_sandbox/privacy_sandbox_service_factory.h"
 
-#include "base/memory/singleton.h"
+#include "base/no_destructor.h"
 #include "chrome/browser/browsing_topics/browsing_topics_service_factory.h"
 #include "chrome/browser/content_settings/cookie_settings_factory.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
@@ -23,7 +23,8 @@
 #endif
 
 PrivacySandboxServiceFactory* PrivacySandboxServiceFactory::GetInstance() {
-  return base::Singleton<PrivacySandboxServiceFactory>::get();
+  static base::NoDestructor<PrivacySandboxServiceFactory> instance;
+  return instance.get();
 }
 
 PrivacySandboxService* PrivacySandboxServiceFactory::GetForProfile(

chrome/browser/privacy_sandbox/privacy_sandbox_service_factory.h

@@ -5,7 +5,7 @@
 #ifndef CHROME_BROWSER_PRIVACY_SANDBOX_PRIVACY_SANDBOX_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_PRIVACY_SANDBOX_PRIVACY_SANDBOX_SERVICE_FACTORY_H_
 
-#include "base/memory/singleton.h"
+#include "base/no_destructor.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
 class PrivacySandboxService;
@@ -17,7 +17,7 @@ class PrivacySandboxServiceFactory : public ProfileKeyedServiceFactory {
   static PrivacySandboxService* GetForProfile(Profile* profile);
 
  private:
-  friend struct base::DefaultSingletonTraits<PrivacySandboxServiceFactory>;
+  friend base::NoDestructor<PrivacySandboxServiceFactory>;
   PrivacySandboxServiceFactory();
   ~PrivacySandboxServiceFactory() override = default;
 

chrome/browser/privacy_sandbox/privacy_sandbox_settings_factory.cc

@@ -4,7 +4,7 @@
 
 #include "chrome/browser/privacy_sandbox/privacy_sandbox_settings_factory.h"
 
-#include "base/memory/singleton.h"
+#include "base/no_destructor.h"
 #include "chrome/browser/content_settings/cookie_settings_factory.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
 #include "chrome/browser/privacy_sandbox/privacy_sandbox_settings_delegate.h"
@@ -14,7 +14,8 @@
 #include "components/privacy_sandbox/privacy_sandbox_settings_impl.h"
 
 PrivacySandboxSettingsFactory* PrivacySandboxSettingsFactory::GetInstance() {
-  return base::Singleton<PrivacySandboxSettingsFactory>::get();
+  static base::NoDestructor<PrivacySandboxSettingsFactory> instance;
+  return instance.get();
 }
 
 privacy_sandbox::PrivacySandboxSettings*

chrome/browser/privacy_sandbox/privacy_sandbox_settings_factory.h

@@ -5,7 +5,7 @@
 #ifndef CHROME_BROWSER_PRIVACY_SANDBOX_PRIVACY_SANDBOX_SETTINGS_FACTORY_H_
 #define CHROME_BROWSER_PRIVACY_SANDBOX_PRIVACY_SANDBOX_SETTINGS_FACTORY_H_
 
-#include "base/memory/singleton.h"
+#include "base/no_destructor.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
 class Profile;
@@ -21,7 +21,7 @@ class PrivacySandboxSettingsFactory : public ProfileKeyedServiceFactory {
       Profile* profile);
 
  private:
-  friend struct base::DefaultSingletonTraits<PrivacySandboxSettingsFactory>;
+  friend base::NoDestructor<PrivacySandboxSettingsFactory>;
   PrivacySandboxSettingsFactory();
   ~PrivacySandboxSettingsFactory() override = default;