Reland "Add result code to complete capture callback to describe exit."

This is a reland of 227443abb3af6e46253ab96063867435cf6358ba

This is an attempted reland of a change that was reverted due to a runtime issue. See crbug/1257040 for the crash report. The differences between the original change and the now updated change can be seen be comparing PS2 with the updated patch sets.

The only changes to fix the crash were:
Checking if the capture mode is active before cancelling the capture and running the callback.

Original change's description:
> Add result code to complete capture callback to describe exit.
>
> This allows the region search controller to differentiate between
> successful captures and user escapes/navigation exits.
>
> Bug: 1254114, b:201456749
> Change-Id: I6daa1969907efe3c95ee0d136df8ea02abcda9b4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3193277
> Commit-Queue: Juan Mojica <juanmojica@google.com>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Ben Goldberger <benwgold@google.com>
> Reviewed-by: Travis Skare <skare@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#928002}

Bug: 1254114, 1257040, b:201456749
Change-Id: I82eb7a55d1944738ffdb5bcb35a4c0bdd4979cec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3209868
Commit-Queue: Juan Mojica <juanmojica@google.com>
Reviewed-by: Travis Skare <skare@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Ben Goldberger <benwgold@google.com>
Cr-Commit-Position: refs/heads/main@{#929510}