diff -r 000000000000 -r 6474c204b198 mobile/android/base/sync/setup/auth/AccountAuthenticator.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/sync/setup/auth/AccountAuthenticator.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,105 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.sync.setup.auth;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+import org.mozilla.gecko.background.common.log.Logger;
+import org.mozilla.gecko.sync.ThreadPool;
+import org.mozilla.gecko.sync.Utils;
+import org.mozilla.gecko.sync.setup.activities.AccountActivity;
+
+public class AccountAuthenticator {
+  private final String LOG_TAG = "AccountAuthenticator";
+
+  private AccountActivity activityCallback;
+  private Queue<AuthenticatorStage> stages;
+
+  // Values for authentication.
+  public String password;
+  public String username;
+
+  public String authServer;
+  public String nodeServer;
+
+  public boolean isSuccess = false;
+  public boolean isCanceled = false;
+
+  public AccountAuthenticator(AccountActivity activity) {
+    activityCallback = activity;
+    prepareStages();
+  }
+
+  private void prepareStages() {
+    stages = new LinkedList<AuthenticatorStage>();
+    stages.add(new EnsureUserExistenceStage());
+    stages.add(new FetchUserNodeStage());
+    stages.add(new AuthenticateAccountStage());
+  }
+
+  public void authenticate(String server, String account, String password) {
+    // Set authentication values.
+    if (!server.endsWith("/")) {
+      server += "/";
+    }
+    nodeServer = server;
+    this.password = password;
+
+    // Calculate and save username hash.
+    try {
+      username = Utils.usernameFromAccount(account);
+    } catch (Exception e) {
+      abort(AuthenticationResult.FAILURE_OTHER, e);
+      return;
+    }
+    Logger.pii(LOG_TAG, "Username:" + username);
+    Logger.debug(LOG_TAG, "Running first stage.");
+    // Start first stage of authentication.
+    runNextStage();
+  }
+
+  /**
+   * Run next stage of authentication.
+   */
+  public void runNextStage() {
+    if (isCanceled) {
+      return;
+    }
+    if (stages.size() == 0) {
+      Logger.debug(LOG_TAG, "Authentication completed.");
+      activityCallback.authCallback(isSuccess ? AuthenticationResult.SUCCESS : AuthenticationResult.FAILURE_PASSWORD);
+      return;
+    }
+    AuthenticatorStage nextStage = stages.remove();
+    try {
+      nextStage.execute(this);
+    } catch (Exception e) {
+      Logger.warn(LOG_TAG, "Unhandled exception in stage " + nextStage);
+      abort(AuthenticationResult.FAILURE_OTHER, e);
+    }
+  }
+
+  /**
+   * Abort authentication.
+   *
+   * @param result
+   *    returned to callback.
+   * @param e
+   *    Exception causing abort.
+   */
+  public void abort(AuthenticationResult result, Exception e) {
+    if (isCanceled) {
+      return;
+    }
+    Logger.warn(LOG_TAG, "Authentication failed.", e);
+    activityCallback.authCallback(result);
+  }
+
+  /* Helper functions */
+  public static void runOnThread(Runnable run) {
+    ThreadPool.run(run);
+  }
+}