Android: Integrates native and java SystemMonitor.

base/android/java/src/org/chromium/base/SystemMonitor.java

Index: base/android/java/src/org/chromium/base/SystemMonitor.java
diff --git a/base/android/java/src/org/chromium/base/SystemMonitor.java b/base/android/java/src/org/chromium/base/SystemMonitor.java
new file mode 100644
index 0000000000000000000000000000000000000000..72a4fb870c7019a1ba041f37d55496a51ee7c762
--- /dev/null
+++ b/base/android/java/src/org/chromium/base/SystemMonitor.java
@@ -0,0 +1,51 @@
+// Copyright (c) 2012 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.base;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.BatteryManager;
+import android.os.Looper;
+
+
+/**
+ * Integrates native SystemMonitor with the java side.
+ */
+@JNINamespace("base::android")
+public class SystemMonitor {
+
+    private static SystemMonitor sInstance;
+
+    public static void create(Context context) {
+        // Can only be called on the UI thread.
+        assert Looper.myLooper() == Looper.getMainLooper();
+        if (sInstance == null) {
+            sInstance = new SystemMonitor();
+            IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
+            Intent batteryStatusIntent = context.registerReceiver(null, ifilter);
+            onBatteryChargingChanged(batteryStatusIntent);
+        }
+    }
+
+    private SystemMonitor() {
+    }
+
+    public static void onBatteryChargingChanged(Intent intent) {
+        if (sInstance == null) {
+            // We may be called by the framework intent-filter before being
+            // fully initialized. This is not a problem, since our constructor
+            // will check for the state later on.
+            return;
+        }
+        int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
+        boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
+                      status == BatteryManager.BATTERY_STATUS_FULL;
+        nativeOnBatteryChargingChanged(isCharging);
+    }
+
+    private static native void nativeOnBatteryChargingChanged(boolean isCharging);
+
+}