GitLab

Converted FakeComObject to DispatchStub using COM best practices.

No attempt was made to restructure the tests. That will come in a
later change.

BUG=1034666

Change-Id: I1ec95c7b792686fc964743ea43bf18d6cfdd7a8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067937
Auto-Submit: Robert Liao <robliao@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743355}