[Android] Implements OS upgrade check and rescheduling

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

Index: components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerFactory.java
diff --git a/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerFactory.java b/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerFactory.java
index 971bebbd5e0576de4f7d72fb8c0745380d30bc50..90fd308b029d9a7f7eb505186ebac11816d25b67 100644
--- a/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerFactory.java
+++ b/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerFactory.java
@@ -4,7 +4,6 @@
 
 package org.chromium.components.background_task_scheduler;
 
-import android.annotation.TargetApi;
 import android.os.Build;
 
 import org.chromium.base.ThreadUtils;
@@ -16,9 +15,8 @@ import org.chromium.base.VisibleForTesting;
 public final class BackgroundTaskSchedulerFactory {
     private static BackgroundTaskScheduler sInstance;
 
-    @TargetApi(Build.VERSION_CODES.M)
-    private static BackgroundTaskSchedulerDelegate getSchedulerDelegate() {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+    static BackgroundTaskSchedulerDelegate getSchedulerDelegateForSdk(int sdkInt) {
+        if (sdkInt >= Build.VERSION_CODES.M) {
             return new BackgroundTaskSchedulerJobService();
         } else {
             return new BackgroundTaskSchedulerGcmNetworkManager();
@@ -31,7 +29,10 @@ public final class BackgroundTaskSchedulerFactory {
      */
     public static BackgroundTaskScheduler getScheduler() {
         ThreadUtils.assertOnUiThread();
-        if (sInstance == null) sInstance = new BackgroundTaskScheduler(getSchedulerDelegate());
+        if (sInstance == null) {
+            sInstance =
+                    new BackgroundTaskScheduler(getSchedulerDelegateForSdk(Build.VERSION.SDK_INT));
+        }
         return sInstance;
     }