Adds base::MatchesUniquePtr to ease lookup by pointer

I also added CreateMatchesUniquePtr() so that you need not specify the
type when creating MatchesUniquePtr().

BUG=none
TEST=none

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: Ifc96ae2397d7f1855f34a4d2969ec19daa6bbeee
Reviewed-on: https://chromium-review.googlesource.com/912516
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536407}
7 files changed