[Android][Signin] Remove ChromeSigninController from FirstRunFlowSequencer.java

Replace calls to ChromeSigninController with IdentityManager API.

Bug: 1074064
Change-Id: Ibe17c08c7e280633b1fac4283a6a7752df911c0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2165345Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Tanmoy Mollik <triploblastic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762846}

chrome/android/java/src/org/chromium/chrome/browser/firstrun/FirstRunFlowSequencer.java

@@ -33,7 +33,6 @@ import org.chromium.chrome.browser.vr.VrModuleProvider;
 import org.chromium.components.embedder_support.util.UrlConstants;
 import org.chromium.components.signin.AccountManagerFacadeProvider;
 import org.chromium.components.signin.ChildAccountStatus;
-import org.chromium.components.signin.ChromeSigninController;
 
 import java.util.Collections;
 import java.util.List;
@@ -94,7 +93,7 @@ public abstract class FirstRunFlowSequencer  {
 
     @VisibleForTesting
     protected boolean isSignedIn() {
-        return ChromeSigninController.get().isSignedIn();
+        return IdentityServicesProvider.get().getIdentityManager().hasPrimaryAccount();
     }
 
     @VisibleForTesting