Chime SDK: Add comment to reserve JobScheduler ids.

Range [111000000, 111999999] is reserved for Chime job scheduler.

Bug: 1013386
Change-Id: Ia211cf20adc4580bcdbb6fcc3303dc0fd4367c4e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1904947Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713893}

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

@@ -13,6 +13,7 @@ public final class TaskIds {
     // BackgroundTaskSchedulerUma#toUmaEnumValueFromTaskId(int) method. Also, if the new task id
     // is related to a BackgroundTask class in //chrome, remember to update
     // ChromeBackgroundTaskFactory#getBackgroundTaskFromTaskId(int).
+    // Id from 111000000 to 111999999 are reserved for internal usage.
     public static final int TEST = 0x00008378;
     public static final int OMAHA_JOB_ID = 0x00011684;