Always use arc::InstanceHolder<T>::GetInstanceForMethod

chrome/browser/chromeos/arc/arc_auth_service.cc

Index: chrome/browser/chromeos/arc/arc_auth_service.cc
diff --git a/chrome/browser/chromeos/arc/arc_auth_service.cc b/chrome/browser/chromeos/arc/arc_auth_service.cc
index fe6a2fc99a490c31084f2a6804525296b8bcc22c..8ab4d66357f88bbe706919fef6fec21bde0dde05 100644
--- a/chrome/browser/chromeos/arc/arc_auth_service.cc
+++ b/chrome/browser/chromeos/arc/arc_auth_service.cc
@@ -229,8 +229,10 @@ bool ArcAuthService::IsAllowedForProfile(const Profile* profile) {
 }
 
 void ArcAuthService::OnInstanceReady() {
-  arc_bridge_service()->auth()->instance()->Init(
-      binding_.CreateInterfacePtrAndBind());
+  auto* instance = arc_bridge_service()->auth()->GetInstanceForMethod("Init");
+  if (!instance)

[Yusuke Sato, 2016/09/21 18:27:48]

Previously, OnInstanceReady() methods were written in various style
(DCHECK(instance), if(!instance), if(!instance) w/ LOG(ERROR), if(!instance) w/
LOG(DFATAL), no null check, etc.) For now, I used 'if(!instance)' w/o logs for
all of them.

[Yusuke Sato, 2016/09/22 22:26:28]

Changed to CHECK() based on your feedback. PTAL.

+    return;
+  instance->Init(binding_.CreateInterfacePtrAndBind());
 }
 
 void ArcAuthService::OnBridgeStopped(ArcBridgeService::StopReason reason) {