mac: Prepare most test code for -Wunused-functions too.

chrome/browser/extensions/api/identity/identity_apitest.cc

Index: chrome/browser/extensions/api/identity/identity_apitest.cc
diff --git a/chrome/browser/extensions/api/identity/identity_apitest.cc b/chrome/browser/extensions/api/identity/identity_apitest.cc
index 305099868dfb09d3ca700b878966d3abc1f0f509..ac3fe6a499537c444a8f16ad1b6f3b9a3f833906 100644
--- a/chrome/browser/extensions/api/identity/identity_apitest.cc
+++ b/chrome/browser/extensions/api/identity/identity_apitest.cc
@@ -188,11 +188,6 @@ class TestOAuth2MintTokenFlow : public OAuth2MintTokenFlow {
   OAuth2MintTokenFlow::Delegate* delegate_;
 };
 
-BrowserContextKeyedService* IdentityAPITestFactory(
-    content::BrowserContext* profile) {
-  return new IdentityAPI(static_cast<Profile*>(profile));
-}
-
 // Waits for a specific GURL to generate a NOTIFICATION_LOAD_STOP event and
 // saves a pointer to the window embedding the WebContents, which can be later
 // closed.