Use GoogleAuthUtil's getToken instead of AccountManager

sync/android/java/src/org/chromium/sync/signin/SystemAccountManagerDelegate.java

Index: sync/android/java/src/org/chromium/sync/signin/SystemAccountManagerDelegate.java
diff --git a/sync/android/java/src/org/chromium/sync/signin/SystemAccountManagerDelegate.java b/sync/android/java/src/org/chromium/sync/signin/SystemAccountManagerDelegate.java
index 75777dd85acde0e749bc10292bebb132bcc49aca..d90280ab3fd3831e84f42aa09d68cc9bdf7a815e 100644
--- a/sync/android/java/src/org/chromium/sync/signin/SystemAccountManagerDelegate.java
+++ b/sync/android/java/src/org/chromium/sync/signin/SystemAccountManagerDelegate.java
@@ -13,14 +13,17 @@ import android.accounts.AuthenticatorException;
 import android.accounts.OperationCanceledException;
 import android.content.Context;
 import android.os.AsyncTask;
-import android.os.Bundle;
-import android.os.Handler;
 import android.os.StrictMode;
 import android.os.SystemClock;
 
+import com.google.android.gms.auth.GoogleAuthException;
+import com.google.android.gms.auth.GoogleAuthUtil;
+import com.google.android.gms.auth.UserRecoverableAuthException;
+
 import org.chromium.base.Callback;
 import org.chromium.base.Log;
 import org.chromium.base.ThreadUtils;
+import org.chromium.base.annotations.MainDex;
 import org.chromium.base.library_loader.LibraryLoader;
 import org.chromium.base.metrics.RecordHistogram;
 
@@ -31,6 +34,7 @@ import java.util.concurrent.TimeUnit;
  * Default implementation of {@link AccountManagerDelegate} which delegates all calls to the
  * Android account manager.
  */
+@MainDex
 public class SystemAccountManagerDelegate implements AccountManagerDelegate {
 
     private final AccountManager mAccountManager;
@@ -70,10 +74,18 @@ public class SystemAccountManagerDelegate implements AccountManagerDelegate {
     }
 
     @Override
-    public AccountManagerFuture<Bundle> getAuthToken(Account account, String authTokenType,
-            boolean notifyAuthFailure, AccountManagerCallback<Bundle> callback, Handler handler) {
-        return mAccountManager.getAuthToken(account, authTokenType, null, notifyAuthFailure,
-                callback, handler);
+    public String getAuthToken(Account account, String authTokenScope) throws AuthException {
+        assert !ThreadUtils.runningOnUiThread();
+        assert AccountManagerHelper.GOOGLE_ACCOUNT_TYPE.equals(account.type);
+        try {
+            return GoogleAuthUtil.getToken(mApplicationContext, account, authTokenScope);
+        } catch (UserRecoverableAuthException ex) {
+            throw new AuthException(false /* isTransientError */, ex.getIntent(), ex);
+        } catch (GoogleAuthException ex) {
+            throw new AuthException(false /* isTransientError */, null, ex);
+        } catch (IOException ex) {
+            throw new AuthException(true /* isTransientError */, null, ex);
+        }
     }
 
     @Override