[Offline pages] Implementation of OfflineBackgroundTask using background_task_scheduler

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerJobService.java

Index: chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerJobService.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerJobService.java b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerJobService.java
index b984f4c7d28a54f27ff0ef5c225244aa65351bf4..1edd938067b00545398719f9d2d157bde14db5fa 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerJobService.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/BackgroundSchedulerJobService.java
@@ -7,7 +7,11 @@ package org.chromium.chrome.browser.offlinepages;
 import android.annotation.TargetApi;
 import android.app.job.JobParameters;
 import android.app.job.JobService;
+import android.content.Context;
 import android.os.Build;
+import android.os.PersistableBundle;
+
+import org.chromium.base.Callback;
 
 /**
  * The background scheduler job service for handling background request in 5.1+.
@@ -16,12 +20,16 @@ import android.os.Build;
 public class BackgroundSchedulerJobService extends JobService {
     @Override
     public boolean onStartJob(JobParameters params) {
-        // TODO(fgorski): Implement and expose in metadata.
-        // Perhaps initialize application context.
-        // Perhaps ensure one job runs at a time only.
-        // Kick off background processing of downloads here.
-        // Processing will happen on a separate thread, and we'll inform OS when done.
-        return true;
+        // TODO(fgorski): Remaining work that we may need to do:
+        // * Expose in metadata.
+        // * Perhaps initialize application context/make sure native portion is loaded.
+        // * Perhaps ensure one job runs at a time only.
+        PersistableBundle extras = params.getExtras();
+        Context context = this;
+
+        BackgroundOfflinerTask task =
+                new BackgroundOfflinerTask(new BackgroundSchedulerProcessorImpl());
+        return task.startBackgroundRequests(context, extras, createCallback(params));
     }
 
     @Override
@@ -32,4 +40,19 @@ public class BackgroundSchedulerJobService extends JobService {
         // If we didn't stop ourselves, that likely means there is more work to do.
         return true;
     }
+
+    private Callback<Boolean> createCallback(final JobParameters params) {
+        return new Callback<Boolean>() {
+            /** TODO(fgorski): Talk to petewil and decide whether result should mean we are done or
+             * that we should be rescheduling the task

[Pete Williamson, 2017/02/21 18:43:43]

Rescheduling is a good idea, but the RC is giving the thread back.  We'd have to
set up a timer in the RC to wake up and reschedule.  We should add a TODO for
that in the RC code.

+             */
+            @Override
+            public void onResult(Boolean result) {
+                boolean needsReschedule = result;
+                // true here is considered: reschedule with backoff,
+                // while false means that we are done.
+                jobFinished(params, needsReschedule);
+            }
+        };
+    }
 }