Clean up onAccessibilityEvent() remove unused mojom fields

This CL also removes unused mojom field (WHITELISTED_PACKAGE_NAME_DEPRECATED).
Android side change (ag/9816677)

Test: ArcAccessibilityHelperBridgeTest.* passes
Bug: b/145316954
Change-Id: Ibac294eddbb45077ec4014b8b5c494599d724dd9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935636
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Sara Kato <sarakato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721817}
3 files changed