diff -r 000000000000 -r 6474c204b198 mobile/android/base/background/common/DateUtils.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/background/common/DateUtils.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,43 @@
+/* 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.background.common;
+
+import java.util.Calendar;
+import java.util.Formatter;
+import java.util.TimeZone;
+
+public class DateUtils {
+  private static final TimeZone UTC = TimeZone.getTimeZone("UTC");
+
+  public static final class DateFormatter {
+    private final Calendar calendar;
+    private final Formatter formatter;
+    private final StringBuilder builder;
+
+    public DateFormatter() {
+      this.calendar = Calendar.getInstance(UTC);
+      this.builder = new StringBuilder();              // So we can reset it.
+      this.formatter = new Formatter(this.builder, null);
+    }
+
+    public String getDateString(long time) {
+      calendar.setTimeInMillis(time);
+      builder.setLength(0);
+      return formatter.format("%04d-%02d-%02d",
+                              calendar.get(Calendar.YEAR),
+                              calendar.get(Calendar.MONTH) + 1,      // 0-indexed.
+                              calendar.get(Calendar.DAY_OF_MONTH))
+                      .toString();
+    }
+
+    public String getDateStringForDay(long day) {
+      return getDateString(GlobalConstants.MILLISECONDS_PER_DAY * day);
+    }
+  }
+
+  public static int getDay(final long time) {
+    return (int) Math.floor(time / GlobalConstants.MILLISECONDS_PER_DAY);
+  }
+}