GN: Define clang_newlib_arm toolchain for NaCl

GN: Define clang_newlib_arm toolchain for NaCl

Define the NaCl toolchain "clang_newlib_arm" with some refactoring.
This makes it possible to build ppapi_nacl_tests on ARM, so enable that.
Also let enable_nacl_browsertests=true function for machines other than
x86-64, since that build more or less works now for all NaCl machines.

R=dpranke@chromium.org
BUG=

Committed: https://crrev.com/8eea7d4bd41472136bf73dccd0d462bd4b2e8124
Cr-Commit-Position: refs/heads/master@{#350280}

[Dirk Pranke, 2015-09-22 23:29:50]

lgtm

https://codereview.chromium.org/1366443002/diff/1/build/toolchain/nacl/BUILD.gn
File build/toolchain/nacl/BUILD.gn (right):

https://codereview.chromium.org/1366443002/diff/1/build/toolchain/nacl/BUILD....
build/toolchain/nacl/BUILD.gn:75: assert(defined(invoker.toolchain_tuple), "Must
define toolchain_tuple")
tuples make me think of lists with two elements, not a two substrings separated
by a dash.

Would 'toolchain_prefix' work for this, or something like it?

[Roland McGrath, 2015-09-22 23:31:38]

mcgrathr@chromium.org changed reviewers:
+ bbudge@chromium.org, phajdan.jr@chromium.org, sky@chromium.org

[Roland McGrath, 2015-09-22 23:31:38]

bbudge: OWNERS review for ppapi/
sky or phajdan.jr: OWNERS review for chrome/test/

Thanks,
Roland

[sky, 2015-09-22 23:44:08]

LGTM

[bbudge, 2015-09-23 00:00:56]

ppapi lgtm

[Roland McGrath, 2015-09-23 00:01:24]

The CQ bit was checked by mcgrathr@chromium.org

[commit-bot: I haz the power, 2015-09-23 00:04:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1366443002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1366443002/20001

[commit-bot: I haz the power, 2015-09-23 00:39:35]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-23 00:40:31]

Patchset 2 (id:??) landed as
https://crrev.com/8eea7d4bd41472136bf73dccd0d462bd4b2e8124
Cr-Commit-Position: refs/heads/master@{#350280}