Create a Promise class to simplify dealing with async results.

chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.signin;
 
 import android.accounts.Account;
 import android.app.Activity;
 import android.app.DialogFragment;
 import android.content.Context;
 import android.os.Handler;
 
 import org.chromium.base.ActivityState;
 import org.chromium.base.ApplicationStatus;
 import org.chromium.base.Callback;
 import org.chromium.base.FieldTrialList;
 import org.chromium.base.Log;
 import org.chromium.base.ObserverList;
+import org.chromium.base.Promise;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.browser.externalauth.ExternalAuthUtils;
 import org.chromium.chrome.browser.externalauth.UserRecoverableErrorHandler;
+import org.chromium.chrome.browser.sync.SyncUserDataWiper;
 import org.chromium.sync.signin.AccountManagerHelper;
 import org.chromium.sync.signin.ChromeSigninController;
 
 import javax.annotation.Nullable;
 
 /**
  * Android wrapper of the SigninManager which provides access from the Java layer.
  * <p/>
  * This class handles common paths during the sign-in and sign-out flows.
  * <p/>
@@ skipping 454 matching lines @@
         Log.d(TAG, "Signin completed.");
         mSignInState = null;
         notifySignInAllowedChanged();
 
         for (SignInStateObserver observer : mSignInStateObservers) {
             observer.onSignedIn();
         }
     }
 
     /**
+     * Invokes signOut and returns a {@link Promise} that will be fulfilled on completion.
+     * This is equivalent to calling {@link #signOut(Runnable callback)} with a callback that
+     * fulfills the returned {@link Promise}.
+     */
+    public Promise<Void> signOutPromise() {
+        final Promise<Void> promise = new Promise<Void>();
+
+        signOut(new Runnable(){
+            @Override
+            public void run() {
+                promise.fulfill(null);
+            }
+        });
+
+        return promise;
+    }
+
+    /**
      * Invokes signOut with no callback or wipeDataHooks.
      */
     public void signOut() {
         signOut(null, null);
     }
 
     /**
      * Invokes signOut() with no wipeDataHooks.
      */
     public void signOut(Runnable callback) {
@@ skipping 69 matching lines @@
         Log.d(TAG, "Signin flow aborted.");
         notifySignInAllowedChanged();
     }
 
     private void wipeProfileData(WipeDataHooks hooks) {
         if (hooks != null) hooks.preWipeData();
         // This will call back to onProfileDataWiped().
         nativeWipeProfileData(mNativeSigninManagerAndroid, hooks);
     }
 
+    /**
+     * Convenience method to return a Promise to be fulfilled when the user's sync data has been
+     * wiped if the parameter is true, or an already fulfilled Promise if the parameter is false.
+     */
+    public static Promise<Void> wipeSyncUserDataIfRequired(boolean required) {
+        if (required) {
+            return SyncUserDataWiper.wipeSyncUserData();
+        } else {
+            return Promise.fulfilled(null);
+        }
+    }
+
     @CalledByNative
     private void onProfileDataWiped(WipeDataHooks hooks) {
         if (hooks != null) hooks.postWipeData();
         onSignOutDone();
     }
 
     @CalledByNative
     private void onNativeSignOut() {
         if (!mSignOutInProgress) {
             signOut();
@@ skipping 49 matching lines @@
     private native void nativeFetchPolicyBeforeSignIn(long nativeSigninManagerAndroid);
     private native void nativeAbortSignIn(long nativeSigninManagerAndroid);
     private native void nativeOnSignInCompleted(long nativeSigninManagerAndroid, String username);
     private native void nativeSignOut(long nativeSigninManagerAndroid);
     private native String nativeGetManagementDomain(long nativeSigninManagerAndroid);
     private native void nativeWipeProfileData(long nativeSigninManagerAndroid, WipeDataHooks hooks);
     private native void nativeClearLastSignedInUser(long nativeSigninManagerAndroid);
     private native void nativeLogInSignedInUser(long nativeSigninManagerAndroid);
     private native boolean nativeIsSignedInOnNative(long nativeSigninManagerAndroid);
 }