[iOS] Add accessor for ProfileOAuth2TokenServiceIOS instance and factory

ios/public/provider/chrome/browser/keyed_service_provider.h

Index: ios/public/provider/chrome/browser/keyed_service_provider.h
diff --git a/ios/public/provider/chrome/browser/keyed_service_provider.h b/ios/public/provider/chrome/browser/keyed_service_provider.h
index ab5bcf1b888440d5fb38fbfcd609866632976026..d7ef72d77cee6ca6cf752fa01b0ed1be5ebb2d75 100644
--- a/ios/public/provider/chrome/browser/keyed_service_provider.h
+++ b/ios/public/provider/chrome/browser/keyed_service_provider.h
@@ -12,6 +12,7 @@ enum class ServiceAccessType;
 
 class KeyedServiceBaseFactory;
 class ProfileOAuth2TokenService;
+class ProfileOAuth2TokenServiceIOS;
 class SigninManager;
 
 namespace autofill {
@@ -46,6 +47,15 @@ class KeyedServiceProvider {
   GetProfileOAuth2TokenServiceForBrowserState(
       ChromeBrowserState* browser_state);
 
+  // Returns the ProfileOAuth2TokenServiceIOS factory for dependencies.
+  virtual KeyedServiceBaseFactory* GetProfileOAuth2TokenServiceIOSFactory();
+
+  // Returns an instance of ProfileOAuth2TokenServiceIOS tied to
+  // |browser_state|.
+  virtual ProfileOAuth2TokenServiceIOS*
+  GetProfileOAuth2TokenServiceIOSForBrowserState(
+      ChromeBrowserState* browser_state);
+
   // Returns the SigninManager factory for dependencies.
   virtual KeyedServiceBaseFactory* GetSigninManagerFactory();