Fix oauth crash

app/src/main/java/com/todoroo/astrid/gtasks/auth/GtasksLoginActivity.java

@@ -10,7 +10,6 @@ import android.app.ProgressDialog;
 import android.content.Intent;
 import android.os.Bundle;
 import com.todoroo.andlib.utility.DialogUtilities;
-import io.reactivex.disposables.CompositeDisposable;
 import javax.inject.Inject;
 import org.tasks.R;
 import org.tasks.data.GoogleTaskAccount;
@@ -29,12 +28,11 @@ import org.tasks.play.AuthResultHandler;
  */
 public class GtasksLoginActivity extends InjectingAppCompatActivity {
 
-  private static final int RC_CHOOSE_ACCOUNT = 10988;
   public static final String EXTRA_ERROR = "extra_error";
+  private static final int RC_CHOOSE_ACCOUNT = 10988;
   @Inject DialogBuilder dialogBuilder;
   @Inject GoogleAccountManager googleAccountManager;
   @Inject GoogleTaskListDao googleTaskListDao;
-  private CompositeDisposable disposables;
 
   @Override
   protected void onCreate(Bundle savedInstanceState) {
@@ -57,18 +55,7 @@ public class GtasksLoginActivity extends InjectingAppCompatActivity {
     getAuthToken(account, pd);
   }
 
-  @Override
-  protected void onPause() {
-    super.onPause();
-
-    if (disposables != null) {
-      disposables.dispose();
-    }
-  }
-
   private void getAuthToken(String a, final ProgressDialog pd) {
-    disposables =
-        new CompositeDisposable(
     googleAccountManager.getTasksAuthToken(
         this,
         a,
@@ -95,7 +82,7 @@ public class GtasksLoginActivity extends InjectingAppCompatActivity {
             DialogUtilities.dismissDialog(GtasksLoginActivity.this, pd);
             finish();
           }
-                }));
+        });
   }
 
   @Override

app/src/main/java/org/tasks/drive/DriveLoginActivity.java

@@ -10,7 +10,6 @@ import android.app.ProgressDialog;
 import android.content.Intent;
 import android.os.Bundle;
 import com.todoroo.andlib.utility.DialogUtilities;
-import io.reactivex.disposables.CompositeDisposable;
 import javax.inject.Inject;
 import org.tasks.R;
 import org.tasks.dialogs.DialogBuilder;
@@ -28,12 +27,11 @@ import org.tasks.preferences.Preferences;
  */
 public class DriveLoginActivity extends InjectingAppCompatActivity {
 
-  private static final int RC_CHOOSE_ACCOUNT = 10988;
   public static final String EXTRA_ERROR = "extra_error";
+  private static final int RC_CHOOSE_ACCOUNT = 10988;
   @Inject DialogBuilder dialogBuilder;
   @Inject GoogleAccountManager googleAccountManager;
   @Inject Preferences preferences;
-  private CompositeDisposable disposables;
 
   @Override
   protected void onCreate(Bundle savedInstanceState) {
@@ -56,18 +54,7 @@ public class DriveLoginActivity extends InjectingAppCompatActivity {
     getAuthToken(account, pd);
   }
 
-  @Override
-  protected void onPause() {
-    super.onPause();
-
-    if (disposables != null) {
-      disposables.dispose();
-    }
-  }
-
   private void getAuthToken(String a, final ProgressDialog pd) {
-    disposables =
-        new CompositeDisposable(
     googleAccountManager.getDriveAuthToken(
         this,
         a,
@@ -86,7 +73,7 @@ public class DriveLoginActivity extends InjectingAppCompatActivity {
             DialogUtilities.dismissDialog(DriveLoginActivity.this, pd);
             finish();
           }
-                }));
+        });
   }
 
   @Override

app/src/main/java/org/tasks/gtasks/GoogleAccountManager.java

@@ -9,6 +9,7 @@ import android.accounts.Account;
 import android.accounts.AccountManager;
 import android.accounts.AuthenticatorException;
 import android.accounts.OperationCanceledException;
+import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
@@ -18,7 +19,6 @@ import com.google.api.services.tasks.TasksScopes;
 import com.google.common.base.Strings;
 import io.reactivex.Single;
 import io.reactivex.android.schedulers.AndroidSchedulers;
-import io.reactivex.disposables.Disposable;
 import io.reactivex.schedulers.Schedulers;
 import java.io.IOException;
 import java.util.Collections;
@@ -83,20 +83,22 @@ public class GoogleAccountManager {
     }
   }
 
-  public Disposable getTasksAuthToken(
+  public void getTasksAuthToken(
       final Activity activity, final String accountName, final AuthResultHandler handler) {
-    return getToken(TasksScopes.TASKS, activity, accountName, handler);
+    getToken(TasksScopes.TASKS, activity, accountName, handler);
   }
 
-  public Disposable getDriveAuthToken(
+  public void getDriveAuthToken(
       final Activity activity, final String accountName, final AuthResultHandler handler) {
-    return getToken(DriveScopes.DRIVE_FILE, activity, accountName, handler);
+    getToken(DriveScopes.DRIVE_FILE, activity, accountName, handler);
   }
 
-  private Disposable getToken(
+  @SuppressWarnings("ResultOfMethodCallIgnored")
+  @SuppressLint("CheckResult")
+  private void getToken(
       String scope, Activity activity, String accountName, AuthResultHandler handler) {
     final Account account = getAccount(accountName);
-    return Single.fromCallable(
+    Single.fromCallable(
             () -> {
               if (account == null) {
                 throw new RuntimeException(