Move android_stack_parser to devtools, adapt and hook it up in `debugger`.

To try it, run:

  mojo/devtools/common/debugger device awsnap

for Chromium-style checkouts (e.g. Mojo) with build in out/android_Debug this
doesn't require any further arguments - regardless of where devtools are
checked in, as long as they are somewhere under the checkout root.

One can set --build-dir and --ndk-dir for non-standard setups.

See #238.

R=etiennej@chromium.org

Review URL: https://codereview.chromium.org/1186113002.

Cr-Mirrored-From: https://github.com/domokit/mojo
Cr-Mirrored-Commit: 188e070f0201c70ddeec63a295cc9ce83df25bda