Rewrite the Android implementation of BatteryMonitor directly in Java.

device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorImpl.java

Index: device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorImpl.java
diff --git a/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorImpl.java b/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorImpl.java
new file mode 100644
index 0000000000000000000000000000000000000000..a7be4f2c7eb274984c11c45a3da8f459d5c9b035
--- /dev/null
+++ b/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorImpl.java
@@ -0,0 +1,59 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.device.battery;
+
+import org.chromium.mojo.system.MojoException;
+import org.chromium.mojom.device.BatteryMonitor;
+import org.chromium.mojom.device.BatteryStatus;
+import org.chromium.mojom.device.BatteryStatusObserver;
+
+/**
+ * Android implementation of the battery monitor service defined in
+ * device/battery/battery_monitor.mojom.
+ */
+public class BatteryMonitorImpl implements BatteryMonitor {
+
+    // Factory that created this instance and notifies it about battery status changes.
+    private final BatteryMonitorFactory mFactory;
+    private boolean mSubscribed;
+
+    private BatteryStatusObserver mClient;
+
+    public BatteryMonitorImpl(BatteryMonitorFactory batteryMonitorFactory) {
+        mFactory = batteryMonitorFactory;
+        mSubscribed = true;
+    }
+
+    private void unsubscribe() {
+        if (mSubscribed) {
+            mFactory.unsubscribe(this);
+            mSubscribed = false;
+        }
+    }
+
+    @Override
+    public void setClient(BatteryStatusObserver client) {
+        mClient = client;
+    }
+
+    @Override
+    public void close() {
+        unsubscribe();
+    }
+
+    @Override
+    public void onConnectionError(MojoException e) {
+        unsubscribe();
+    }
+
+    /**
+     * Notifies the client passing the given battery status information.
+     */
+    void didChange(BatteryStatus batteryStatus) {
+        if (mClient != null) {
+            mClient.didChange(batteryStatus);
+        }
+    };
+}