[Android] BackgroundTaskScheduler reschedule implementation

components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java

Index: components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java
diff --git a/components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java b/components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java
index f917c6f3473f15bb709e6891585961da0e9c1438..947b51cf0996f55ca9e982784b0a1a01e7162878 100644
--- a/components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java
+++ b/components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerPrefsTest.java
@@ -96,4 +96,14 @@ public class BackgroundTaskSchedulerPrefsTest {
         assertTrue("TASK_2 class name in scheduled tasks.",
                 scheduledTasks.contains(TASK_2.getBackgroundTaskClass().getName()));
     }
+
+    @Test
+    @Feature("BackgroundTaskScheduler")
+    public void testRemoveAllTasks() {
+        BackgroundTaskSchedulerPrefs.addScheduledTask(TASK_1);
+        BackgroundTaskSchedulerPrefs.addScheduledTask(TASK_2);
+        BackgroundTaskSchedulerPrefs.removeAllTasks();
+        assertTrue("We are expecting a all tasks to be gone.",
+                BackgroundTaskSchedulerPrefs.getScheduledTasks().isEmpty());
+    }
 }