DO NOT MERGE Add a new WakeupMessage class

This is useful when using the new AlarmManager direct callback
interface to wake up the system and request that an object whose
API consists of messages (such as a StateMachine) perform some
action.

In this situation, using AlarmManager.onAlarmListener by itself
will wake up the system to send the message, but does not
guarantee that the system will be awake until the target object
has processed it. This is because as soon as the onAlarmListener
sends the message and returns, the system is free to go to sleep
again.

Bug: 20157436
Bug: 25823676
Cherry-picked WakeupMessage.java from 9d3aadb24778cc36a350a04b088d2ed7ee3790e1
Change-Id: Idff20029d287f26347441a2523b7fb20eda6a8b0
diff --git a/core/java/com/android/internal/util/WakeupMessage.java b/core/java/com/android/internal/util/WakeupMessage.java
new file mode 100644
index 0000000..77859b8
--- /dev/null
+++ b/core/java/com/android/internal/util/WakeupMessage.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.util;
+
+import android.app.AlarmManager;
+import android.content.Context;
+import android.os.Handler;
+import android.os.Message;
+
+ /**
+ * An AlarmListener that sends the specified message to a Handler and keeps the system awake until
+ * the message is processed.
+ *
+ * This is useful when using the AlarmManager direct callback interface to wake up the system and
+ * request that an object whose API consists of messages (such as a StateMachine) perform some
+ * action.
+ *
+ * In this situation, using AlarmManager.onAlarmListener by itself will wake up the system to send
+ * the message, but does not guarantee that the system will be awake until the target object has
+ * processed it. This is because as soon as the onAlarmListener sends the message and returns, the
+ * AlarmManager releases its wakelock and the system is free to go to sleep again.
+ *
+ */
+public class WakeupMessage implements AlarmManager.OnAlarmListener {
+    private static AlarmManager sAlarmManager;
+    private final Handler mHandler;
+    private final String mCmdName;
+    private final int mCmd, mArg1, mArg2;
+
+    public WakeupMessage(Context context, Handler handler,
+            String cmdName, int cmd, int arg1, int arg2) {
+        if (sAlarmManager == null) {
+            sAlarmManager = context.getSystemService(AlarmManager.class);
+        }
+        mHandler = handler;
+        mCmdName = cmdName;
+        mCmd = cmd;
+        mArg1 = arg1;
+        mArg2 = arg2;
+    }
+
+    public WakeupMessage(Context context, Handler handler, String cmdName, int cmd, int arg1) {
+        this(context, handler, cmdName, cmd, arg1, 0);
+    }
+
+    public WakeupMessage(Context context, Handler handler, String cmdName, int cmd) {
+        this(context, handler, cmdName, cmd, 0, 0);
+    }
+
+    public void schedule(long when) {
+        sAlarmManager.setExact(
+                AlarmManager.ELAPSED_REALTIME_WAKEUP, when, mCmdName, this, mHandler);
+    }
+
+    public void cancel() {
+        sAlarmManager.cancel(this);
+    }
+
+    @Override
+    public void onAlarm() {
+        Message msg = mHandler.obtainMessage(mCmd, mArg1, mArg2);
+        mHandler.handleMessage(msg);
+        msg.recycle();
+    }
+}