win: Provide broken CHECK()ing dummy CaptureContext() for cross builds
win: Provide broken CHECK()ing dummy CaptureContext() for cross builds

This upstreams
https://chromium.googlesource.com/chromium/src/+/fc1ac734b09f7f8017c01d66947b3d17b1ba1718
(slightly modified).

This dummy implementation is not used by Crashpad anywhere at all, and
is only used by Crashpad in Chromium during a cross build targeting
Windows without the benefit of Microsoft’s ml.exe/ml64.exe assembler.
Strictly speaking, this file does not need to be checked in to the
Crashpad repository, but since Chromium needs it to unblock its
not-production-ready cross build for Windows, it’s being landed here to
avoid Chromium’s copy of Crashpad appearing as modified or “dirty”
relative to this upstream copy. (Even though this file is really dirty.)

Bug: chromium:762167
Change-Id: Ibfdc316c1f5fe81d4b3a1d86f4032adccac467e5
Reviewed-on: https://chromium-review.googlesource.com/734102
Reviewed-by: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>
Commit-Queue: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>

chromium/crashpad,atom/crashpad,chromium/crashpad,chromium/crashpad,atom/crashpad,atom/crashpad