Read later: Use BrowserContextKeyedServiceFactory for Android glue.

ReadingListManagerFactory should be BrowserContextKeyedServiceFactory
instead of SimpleKeyedServiceFactory, since reduced mode won't work
for sync and ReadingListModel.

Also we build components/reading_list to Android APK, which causes
android binary size increase.

Bug: 1128074
Binary-Size: Size increase is unavoidable (see above).
Change-Id: If5393fa5dfb133b35c1ff1b17bf709f31f8815ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441204
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Brandon Wylie <wylieb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813899}