Implements the non-deprecated builder.

Any class inheriting `BrowserContextKeyedServiceFactory` should
implements either `BuildServiceInstanceForBrowserContext` or
`BuildServiceInstanceFor`. The second one being deprecated, this CLreplaces it by the first one.
This also ensures that, instead of applying `WrapUnique` to a `new` raw ptr, it directly uses `make_unique`.

Bug: 40249337
Change-Id: Ia2e99f80a43e0b56449aa5585d810bdd832c1668
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4797779
Reviewed-by: Stefan Kuhne <skuhne@chromium.org>
Auto-Submit: Arthur Milchior <arthurmilchior@chromium.org>
Commit-Queue: Arthur Milchior <arthurmilchior@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1378740}

apps/saved_files_service_factory.cc

@@ -40,9 +40,10 @@ SavedFilesServiceFactory::SavedFilesServiceFactory()
 
 SavedFilesServiceFactory::~SavedFilesServiceFactory() = default;
 
-KeyedService* SavedFilesServiceFactory::BuildServiceInstanceFor(
+std::unique_ptr<KeyedService>
+SavedFilesServiceFactory::BuildServiceInstanceForBrowserContext(
     content::BrowserContext* context) const {
-  return new SavedFilesService(context);
+  return std::make_unique<SavedFilesService>(context);
 }
 
 content::BrowserContext* SavedFilesServiceFactory::GetBrowserContextToUse(

apps/saved_files_service_factory.h

@@ -35,7 +35,7 @@ class SavedFilesServiceFactory : public BrowserContextKeyedServiceFactory {
   ~SavedFilesServiceFactory() override;
   friend struct base::DefaultSingletonTraits<SavedFilesServiceFactory>;
 
-  KeyedService* BuildServiceInstanceFor(
+  std::unique_ptr<KeyedService> BuildServiceInstanceForBrowserContext(
       content::BrowserContext* context) const override;
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;