[android] Add JobScheduler-based BackgroundTaskScheduler.

components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/TaskParameters.java

+// Copyright 2017 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.background_task_scheduler;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+
+/**
+ * TaskParameters are passed to {@link BackgroundTask}s whenever they are invoked. It contains the
+ * task ID and the extras that the caller of
+ * {@link BackgroundTaskScheduler#schedule(Context, TaskInfo)} passed in with the {@link TaskInfo}.
+ */
+public class TaskParameters {
+    private final int mTaskId;
+    private final Bundle mExtras;
+
+    private TaskParameters(Builder builder) {
+        mTaskId = builder.mTaskId;
+        mExtras = builder.mExtras == null ? new Bundle() : builder.mExtras;
+    }
+
+    /**
+     * @return the task ID.
+     */
+    public int getTaskId() {
+        return mTaskId;
+    }
+
+    /**
+     * @return the extras for this task.
+     */
+    @NonNull
+    public Bundle getExtras() {
+        return mExtras;
+    }
+
+    static Builder create(int taskId) {
+        return new Builder(taskId);
+    }
+
+    static final class Builder {
+        private final int mTaskId;
+        private Bundle mExtras;
+
+        Builder(int taskId) {
+            mTaskId = taskId;
+        }
+
+        Builder addExtras(Bundle extras) {
+            mExtras = extras;
+            return this;
+        }
+
+        TaskParameters build() {
+            return new TaskParameters(this);
+        }
+    }
+}