diff -r 000000000000 -r 6474c204b198 mobile/android/base/Telemetry.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/Telemetry.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,147 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * 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;
+
+import org.mozilla.gecko.mozglue.RobocopTarget;
+
+import android.os.SystemClock;
+import android.util.Log;
+
+/**
+ * All telemetry times are relative to one of two clocks:
+ * 
+ * * Real time since the device was booted, including deep sleep. Use this
+ *   as a substitute for wall clock.
+ * * Uptime since the device was booted, excluding deep sleep. Use this to
+ *   avoid timing a user activity when their phone is in their pocket!
+ *
+ * The majority of methods in this class are defined in terms of real time.
+ */
+@RobocopTarget
+public class Telemetry {
+    private static final String LOGTAG = "Telemetry";
+
+    public static long uptime() {
+        return SystemClock.uptimeMillis();
+    }
+
+    public static long realtime() {
+        return SystemClock.elapsedRealtime();
+    }
+
+    // Define new histograms in:
+    // toolkit/components/telemetry/Histograms.json
+    public static void HistogramAdd(String name, int value) {
+        GeckoEvent event = GeckoEvent.createTelemetryHistogramAddEvent(name, value);
+        GeckoAppShell.sendEventToGecko(event);
+    }
+
+    public abstract static class Timer {
+        private final long mStartTime;
+        private final String mName;
+
+        private volatile boolean mHasFinished = false;
+        private volatile long mElapsed = -1;
+
+        protected abstract long now();
+
+        public Timer(String name) {
+            mName = name;
+            mStartTime = now();
+        }
+
+        public void cancel() {
+            mHasFinished = true;
+        }
+
+        public long getElapsed() {
+          return mElapsed;
+        }
+
+        public void stop() {
+            // Only the first stop counts.
+            if (mHasFinished) {
+                return;
+            }
+
+            mHasFinished = true;
+
+            final long elapsed = now() - mStartTime;
+            if (elapsed < 0) {
+                Log.e(LOGTAG, "Current time less than start time -- clock shenanigans?");
+                return;
+            }
+
+            mElapsed = elapsed;
+            if (elapsed > Integer.MAX_VALUE) {
+                Log.e(LOGTAG, "Duration of " + elapsed + "ms is too great to add to histogram.");
+                return;
+            }
+
+            HistogramAdd(mName, (int)(elapsed));
+        }
+    }
+
+    public static class RealtimeTimer extends Timer {
+        public RealtimeTimer(String name) {
+            super(name);
+        }
+
+        @Override
+        protected long now() {
+            return Telemetry.realtime();
+        }
+    }
+
+    public static class UptimeTimer extends Timer {
+        public UptimeTimer(String name) {
+            super(name);
+        }
+
+        @Override
+        protected long now() {
+            return Telemetry.uptime();
+        }
+    }
+
+    public static void startUISession(String sessionName) {
+        Log.d(LOGTAG, "StartUISession: " + sessionName);
+        GeckoEvent event = GeckoEvent.createTelemetryUISessionStartEvent(sessionName, realtime());
+        GeckoAppShell.sendEventToGecko(event);
+    }
+
+    public static void stopUISession(String sessionName, String reason) {
+        Log.d(LOGTAG, "StopUISession: " + sessionName + ", reason=" + reason);
+        GeckoEvent event = GeckoEvent.createTelemetryUISessionStopEvent(sessionName, reason, realtime());
+        GeckoAppShell.sendEventToGecko(event);
+    }
+
+    public static void stopUISession(String sessionName) {
+        stopUISession(sessionName, null);
+    }
+
+    public static void sendUIEvent(String action, String method, long timestamp, String extras) {
+        Log.d(LOGTAG, "SendUIEvent: action = " + action + " method = " + method + " timestamp = " + timestamp + " extras = " + extras);
+        GeckoEvent event = GeckoEvent.createTelemetryUIEvent(action, method, timestamp, extras);
+        GeckoAppShell.sendEventToGecko(event);
+    }
+
+    public static void sendUIEvent(String action, String method, long timestamp) {
+        sendUIEvent(action, method, timestamp, null);
+    }
+
+    public static void sendUIEvent(String action, String method, String extras) {
+        sendUIEvent(action, method, realtime(), extras);
+    }
+
+    public static void sendUIEvent(String action, String method) {
+        sendUIEvent(action, method, realtime(), null);
+    }
+
+    public static void sendUIEvent(String action) {
+        sendUIEvent(action, null, realtime(), null);
+    }
+}