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Current implementation will not return callback until succeed. This
patch adds a limit to the max number of retries. This patch also changes
the backoff logic to use backoff entry.

Bug: b/169250512
Test: added new tests.
Change-Id: Id421a152dc7fe6ce3f365086d16c6e611b4fc001
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2427082
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810840}