Deprecate sign-in from share.

ios/chrome/browser/signin/constants.h

Index: ios/chrome/browser/signin/constants.h
diff --git a/ios/chrome/browser/signin/constants.h b/ios/chrome/browser/signin/constants.h
index f0871cd5b59e090232d9bab71bfd74c4eb0aec9b..2ff5f98785cb4d450f8e7f22394a420cea28e117 100644
--- a/ios/chrome/browser/signin/constants.h
+++ b/ios/chrome/browser/signin/constants.h
@@ -38,7 +38,8 @@ typedef enum {
   // Sign in operation was started from settings.
   SIGN_IN_SOURCE_SETTINGS,
   // Sign in operation was started from as a pre-requisite of share operation.
-  SIGN_IN_SOURCE_SHARE,
+  // Deprecated since M53.
+  SIGN_IN_SOURCE_SHARE_DEPRECATED,

[sdefresne, 2016/05/30 14:16:29]

We probably need to update Signin.IOSSignInSource history too, don't we?

[jif-google, 2016/05/30 14:29:26]

https://critique.corp.google.com/#review/123579885

[sdefresne, 2016/06/02 17:16:24]

As the enum is public should we also upstream the histogram definition
(especially if we mention it in the comment). If yes, this should be done in a
separate CL. Can you create a bug to track this?

   // Sign in operation was started from as a pre-requisite of a print operation.
   SIGN_IN_SOURCE_PRINT,
   // Sign in operation was started from the re-sign in infobar.