Reland "Refactor crashpad_handler binary on macOS"

This is a reland of c5a20e34006837ab54037ea75e9a7a00bf1275e3. Trying to
rename chrome_crashpad_handler to crashpad_handler in the final output
led to contortions in the build, instead invoke the handler using the new
name.

Original change's description:
> Refactor crashpad_handler binary on macOS
>
> In order to define custom UserStreamDataSources, we need a
> chromium-built crashpad_handler binary. This change refactors the
> crashpad_handler executable to be built within chromium as
> chrome_crashpad_handler and moved into it's final destination under the
> original 'crashpad_handler' name.
>
> Bug: 912286
> Change-Id: I0f52028ae4c149823b30747589e2dd94225694c6
> Reviewed-on: https://chromium-review.googlesource.com/c/1449330
> Reviewed-by: Lei Zhang <thestig@chromium.org>
> Reviewed-by: Peter Beverloo <peter@chromium.org>
> Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
> Reviewed-by: Mark Mentovai <mark@chromium.org>
> Commit-Queue: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#629394}

TBR=peter@chromium.org,pfeldman@chromium.org

Bug: 912286
Change-Id: Idabc3f3bf547afe0c63ce0910641f83ec0106304
Reviewed-on: https://chromium-review.googlesource.com/c/1455724
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629713}
6 files changed