Refactoring DevToolsBridgeServer.

components/devtools_bridge/android/java/src/org/chromium/components/devtools_bridge/ServiceLifetimeManager.java

Index: components/devtools_bridge/android/java/src/org/chromium/components/devtools_bridge/ServiceLifetimeManager.java
diff --git a/components/devtools_bridge/android/java/src/org/chromium/components/devtools_bridge/ServiceLifetimeManager.java b/components/devtools_bridge/android/java/src/org/chromium/components/devtools_bridge/ServiceLifetimeManager.java
new file mode 100644
index 0000000000000000000000000000000000000000..29f0f3b32b6d01cda61d871032037add885833d3
--- /dev/null
+++ b/components/devtools_bridge/android/java/src/org/chromium/components/devtools_bridge/ServiceLifetimeManager.java
@@ -0,0 +1,83 @@
+// 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.components.devtools_bridge;
+
+import android.app.IntentService;
+import android.app.Service;
+import android.content.Context;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.PowerManager;
+
+/**
+ * Tracks count of running tasks and stops the service when all tasks completed. Supposed to be
+ * a part of a service.
+ *
+ * Usage:
+ * class MyService extends Service {
+ *     public int onStartCommand(Intent intent, int flags, int startId) {
+ *         Runnable intentHandlingTask = mLifetimeManager.startTask(startId);
+ *         ...
+ *         intentHandlingTask.run(); // Stops self if no other task started.
+ *         return START_NOT_STICKY;
+ *     }
+ * }
+ */
+class ServiceLifetimeManager {
+    private final Service mService;
+    private final String mWakeLockKey;
+    private int mLastStartId = -1;
+    private int mActiveTasks = 0;
+    private PowerManager.WakeLock mWakeLock;
+
+    public ServiceLifetimeManager(Service service, String wakeLockKey) {
+        // IntentService is incompatible with this class because it manages lifetime on its own.
+        assert !(service instanceof IntentService);
+
+        mService = service;
+        mWakeLockKey = wakeLockKey;
+    }
+
+    public Runnable startTask(int startId) {
+        mLastStartId = startId;
+        return startTask();
+    }
+
+    public Runnable startTask() {
+        assert isCalledOnServiceLooper();
+        if (mActiveTasks == 0) {
+            if (mWakeLock == null) {
+                PowerManager pm = (PowerManager) mService.getSystemService(Context.POWER_SERVICE);
+                mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, mWakeLockKey);
+            }
+            mWakeLock.acquire();
+        }
+        mActiveTasks++;
+        return new TaskCompletionHandler();
+    }
+
+    private boolean isCalledOnServiceLooper() {
+        return mService.getMainLooper() == Looper.myLooper();
+    }
+
+    private class TaskCompletionHandler implements Runnable {
+        private boolean mCompleted = false;
+
+        @Override
+        public void run() {
+            if (!isCalledOnServiceLooper()) {
+                new Handler(mService.getMainLooper()).post(this);
+                return;
+            }
+            if (mCompleted) return;
+
+            if (--mActiveTasks == 0) {
+                mWakeLock.release();
+                mService.stopSelf(mLastStartId);
+            }
+            mCompleted = true;
+        }
+    }
+}