The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/054a0dccede86d525f94d516285e79adde6fe6f1

commit 054a0dccede86d525f94d516285e79adde6fe6f1
Author: thildebr <thildebr@chromium.org>
Date: Wed Jun 28 21:01:51 2017

Add a JUnit test rule for clearing app data prior to testing.

Having a test rule for clearing app data allows us to use RuleChain to ensure
we clear app data before initializing the browser process. Currently, many
chrome/browser tests that use ApplicationData.clearAppData are flaky because
of a race condition between clearing app data and initializing the browser.

BUG= 737610 

Review-Url: https://codereview.chromium.org/2962893002
Cr-Commit-Position: refs/heads/master@{#483136}

[modify] https://crrev.com/054a0dccede86d525f94d516285e79adde6fe6f1/chrome/android/java_sources.gni
[add] https://crrev.com/054a0dccede86d525f94d516285e79adde6fe6f1/chrome/android/javatests/src/org/chromium/chrome/browser/test/ClearAppDataTestRule.java