This fixes a few style warnings:

 * auto should not deduce to raw pointer type
 * inlined virtual methods are not allowed
 * non-trivial constructors and destructors should be explicit
 * inlined non-trivial constructors should not be in-class
 * missing override keywords

Bug: angleproject:3069
Change-Id: I3b3e55683691da3ebf6da06a5d3c729c71b6ee53
Reviewed-on: https://chromium-review.googlesource.com/c/1407640
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>