diff -r 000000000000 -r 6474c204b198 mobile/android/base/sync/CredentialException.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/sync/CredentialException.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,55 @@
+/* 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;
+
+import android.content.SyncResult;
+
+/**
+ * There was a problem with the Sync account's credentials: bad username,
+ * missing password, malformed sync key, etc.
+ */
+public abstract class CredentialException extends SyncException {
+  private static final long serialVersionUID = 833010553314100538L;
+
+  public CredentialException() {
+    super();
+  }
+
+  public CredentialException(final Throwable e) {
+    super(e);
+  }
+
+  public void updateStats(GlobalSession globalSession, SyncResult syncResult) {
+    syncResult.stats.numAuthExceptions += 1;
+  }
+
+  /**
+   * No credentials at all.
+   */
+  public static class MissingAllCredentialsException extends CredentialException {
+    private static final long serialVersionUID = 3763937096217604611L;
+
+    public MissingAllCredentialsException() {
+      super();
+    }
+
+    public MissingAllCredentialsException(final Throwable e) {
+      super(e);
+    }
+  }
+
+  /**
+   * Some credential is missing.
+   */
+  public static class MissingCredentialException extends CredentialException {
+    private static final long serialVersionUID = -7543031216547596248L;
+
+    public final String missingCredential;
+
+    public MissingCredentialException(final String missingCredential) {
+      this.missingCredential = missingCredential;
+    }
+  }
+}