Replace direct access to kGoogleServicesUsername with calls to SigninManager.

chrome/browser/sync/profile_sync_service.cc

Index: chrome/browser/sync/profile_sync_service.cc
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 2643f51ae95bfad483bb02e2e49094336ee1bb84..755845550b5e1f811719bcf82ac3922697d5dd7d 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -2501,10 +2501,7 @@ SigninManagerBase* ProfileSyncService::signin() const {
 void ProfileSyncService::UnsuppressAndStart() {
   DCHECK(profile_);
   sync_prefs_.SetStartSuppressed(false);
-  if (signin_.get() && !signin_->GetOriginal()->IsAuthenticated()) {
-    signin_->GetOriginal()->SetAuthenticatedUsername(
-        profile_->GetPrefs()->GetString(prefs::kGoogleServicesUsername));

[Nicolas Zea, 2014/12/04 17:57:39]

Is this no longer necessary? Was the signin manager previously not always fully
initialized, but it is now?

[Roger Tawa OOO till Jul 10th, 2014/12/04 22:26:47]

Well, that's a question for you :-)  Pavel tracked down the introduction of this
to an old CL:

https://codereview.chromium.org/8332023/diff/8002/chrome/browser/sync/profile...

but the comment is no longer applicable.  Today, if you look at the
implementation of signin_->GetOriginal()->IsAuthenticated(), that is true iff
!authenticated_account_id_.empty().  That member is initialized either from:

1/ prefs::kGoogleServicesUsername, OR
2/ by a call to SetAuthenticatedUsername(), which sets
prefs::kGoogleServicesUsername

So if IsAuthenticated() is false, then prefs::kGoogleServicesUsername is empty,
and SetAuthenticatedUsername() would DCHECK.

I left a DCHECK to see if my assumption is wrong, but it was not hit in any of
the unit tests or browser tests, or in any of the manual testing I did.

-  }
+  DCHECK(!signin_.get() || signin_->GetOriginal()->IsAuthenticated());
   startup_controller_.TryStart();
 }