[Android] BackgroundTaskScheduler reschedule implementation

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

Index: components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefs.java
diff --git a/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefs.java b/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefs.java
index 4e03fd31a7b80e337fff9901fa70c6a7d4af2088..1a71d34d43da3b7f25b8f89722f520f36c5d4896 100644
--- a/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefs.java
+++ b/components/background_task_scheduler/android/java/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefs.java
@@ -74,6 +74,11 @@ public class BackgroundTaskSchedulerPrefs {
         return scheduledTasksClassNames;
     }
 
+    /** Removes all scheduled tasks from shared preferences store. */
+    public static void removeAllTasks() {
+        ContextUtils.getAppSharedPreferences().edit().remove(KEY_SCHEDULED_TASKS).apply();
+    }
+
     private static void updateScheduledTasks(SharedPreferences prefs, Set<String> tasks) {
         SharedPreferences.Editor editor = prefs.edit();
         editor.putStringSet(KEY_SCHEDULED_TASKS, tasks);