diff -r 000000000000 -r 6474c204b198 mobile/android/base/sync/PrefsBackoffHandler.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/sync/PrefsBackoffHandler.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,59 @@
+/* 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.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+
+public class PrefsBackoffHandler implements BackoffHandler {
+  public static final String PREF_EARLIEST_NEXT = "earliestnext";
+
+  private final SharedPreferences prefs;
+  private final String prefEarliest;
+
+  public PrefsBackoffHandler(final SharedPreferences prefs, final String prefSuffix) {
+    if (prefs == null) {
+      throw new IllegalArgumentException("prefs must not be null.");
+    }
+    this.prefs = prefs;
+    this.prefEarliest = PREF_EARLIEST_NEXT + "." + prefSuffix;
+  }
+
+  @Override
+  public synchronized long getEarliestNextRequest() {
+    return prefs.getLong(prefEarliest, 0);
+  }
+
+  @Override
+  public synchronized void setEarliestNextRequest(final long next) {
+    final Editor edit = prefs.edit();
+    edit.putLong(prefEarliest, next);
+    edit.commit();
+  }
+
+  @Override
+  public synchronized void extendEarliestNextRequest(final long next) {
+    if (prefs.getLong(prefEarliest, 0) >= next) {
+      return;
+    }
+    final Editor edit = prefs.edit();
+    edit.putLong(prefEarliest, next);
+    edit.commit();
+  }
+
+  /**
+   * Return the number of milliseconds until we're allowed to touch the server again,
+   * or 0 if now is fine.
+   */
+  @Override
+  public long delayMilliseconds() {
+    long earliestNextRequest = getEarliestNextRequest();
+    if (earliestNextRequest <= 0) {
+      return 0;
+    }
+    long now = System.currentTimeMillis();
+    return Math.max(0, earliestNextRequest - now);
+  }
+}
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