Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/browser/web_data_service_factory.h

Index: ios/chrome/browser/web_data_service_factory.h
diff --git a/ios/chrome/browser/web_data_service_factory.h b/ios/chrome/browser/web_data_service_factory.h
index fee7432c3cfb2f1545b4a1d31d1beca81d802d1c..99801be624f9aa0cd4b3923125d3537069e2656a 100644
--- a/ios/chrome/browser/web_data_service_factory.h
+++ b/ios/chrome/browser/web_data_service_factory.h
@@ -5,9 +5,10 @@
 #ifndef IOS_CHROME_BROWSER_WEB_DATA_SERVICE_FACTORY_H_
 #define IOS_CHROME_BROWSER_WEB_DATA_SERVICE_FACTORY_H_
 
+#include <memory>
+
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
 
 namespace base {
@@ -64,7 +65,7 @@ class WebDataServiceFactory : public BrowserStateKeyedServiceFactory {
   ~WebDataServiceFactory() override;
 
   // BrowserStateKeyedServiceFactory implementation.
-  scoped_ptr<KeyedService> BuildServiceInstanceFor(
+  std::unique_ptr<KeyedService> BuildServiceInstanceFor(
       web::BrowserState* context) const override;
   web::BrowserState* GetBrowserStateToUse(
       web::BrowserState* context) const override;