[ObjC ARC] Converts components/signin/ios/browser:browser to ARC.

components/signin/ios/browser/merge_session_observer_bridge.h

Index: components/signin/ios/browser/merge_session_observer_bridge.h
diff --git a/components/signin/ios/browser/merge_session_observer_bridge.h b/components/signin/ios/browser/merge_session_observer_bridge.h
index 8137dbbf1d0532e01b0bf04b595c977a3f1a044f..d667b32da10f384ae7a41d5d57cabbe41001442d 100644
--- a/components/signin/ios/browser/merge_session_observer_bridge.h
+++ b/components/signin/ios/browser/merge_session_observer_bridge.h
@@ -9,6 +9,7 @@
 
 #include <string>
 
+#import "base/ios/weak_nsobject.h"
 #include "base/macros.h"
 #include "components/signin/core/browser/gaia_cookie_manager_service.h"
 
@@ -35,7 +36,7 @@ class MergeSessionObserverBridge : public GaiaCookieManagerService::Observer {
       const GoogleServiceAuthError& error) override;
 
  private:
-  id<MergeSessionObserverBridgeDelegate> delegate_;
+  base::WeakNSProtocol<id<MergeSessionObserverBridgeDelegate>> delegate_;

[stkhapugin, 2017/06/13 12:18:55]

This seems to be included only from the corresponding .mm, so you can try making
this __weak instead. 

[msarda, 2017/06/13 13:15:30]

I do not know that much about ARC transition, so this is probably a newbie
question: Shouldn't this be __weak (or maybe a weak property) instead of
base::WeakNSProtocol?

[marq (ping after 24h), 2017/06/15 09:27:33]

Because it's in a header, it can only be __weak if it's only included in ARC
targets. Otherwise it needs to be a WeakNSProtocol. It looks like we can change
this one, though.

   GaiaCookieManagerService* cookie_manager_service_;
 
   DISALLOW_COPY_AND_ASSIGN(MergeSessionObserverBridge);