[ui] Add HWND id to HWNDMessageHandler::OnWndProc

This will be used to check whether events seen in UpdateDwmFrame jank
(see bug) is the OS spamming multiple events for the same HWND or the
same events for each HWND owned by Chrome.

Bug: 1179852
Change-Id: I2d3af24d14583b247a076250e85fcab961f61e53
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2713345


Commit-Queue: Gabriel Charette <gab@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#859767}