Fix chromium-style errors

This is to fix the following chromium-style errors:

'virtual' is redundant; 'override' implies 'virtual'.

Classes that are ref-counted should have explicit destructors that are
declared protected or private.

Bug: None
Test: CQ
Change-Id: I9a9dd1aa5437c392c4f34a5fbdf856798cf8ccb2
Reviewed-by: Sergey Volk <>
Reviewed-by: Sean Topping <>
Reviewed-by: Dan Sanders <>
Commit-Queue: Yuchen Liu <>
Cr-Commit-Position: refs/heads/master@{#623796}
1 file changed