Fix GN os, cpu defaults for Android builds.

Fix GN os, cpu defaults for Android builds.

We would like to be able to default to the ARM CPU for
Android builds, not the host cpu (so that you can get the
default Android build by just specifying os="android");
prior to my cpu_arch -> target_cpu changes, this was the
case, but I accidentally broke this.

However, the target_cpu changes at least allow us to remove
the target_arch hack which was how they were accomplishing
this before :).

TBR=brettw@chromium.org
R=cjhopman@chromium.org
BUG=344767
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:android_chromium_gn_compile_dbg,android_chromium_gn_compile_rel;tryserver.chromium.win:win8_chromium_gn_rel,win8_chromium_gn_dbg;tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg

Committed: https://crrev.com/55187fbe2d3264d4c31432e2f8a77f094d7c986b
Cr-Commit-Position: refs/heads/master@{#317419}

[Dirk Pranke, 2015-02-20 20:06:50]

https://codereview.chromium.org/946683002/diff/1/build/config/BUILDCONFIG.gn
File build/config/BUILDCONFIG.gn (left):

https://codereview.chromium.org/946683002/diff/1/build/config/BUILDCONFIG.gn#...
build/config/BUILDCONFIG.gn:120: target_arch = "arm"
I think it's perhaps best to just cut straight to getting users to specify
target_cpu instead of target_arch, if they need to do an x86 android build (or
some other variant). I'm not even sure if any non-arm Android build actually
works at the moment, so I don't know if anyone is actually using non-arm values,


It would not be hard to support target_arch for backwards compatibility for some
time, though, if that would be preferred.

https://codereview.chromium.org/946683002/diff/1/build/config/BUILDCONFIG.gn#...
build/config/BUILDCONFIG.gn:227: current_cpu = target_arch
This was the thing I broke in https://codereview.chromium.org/913373002/ ; this
should've been target_cpu, not current_cpu.

[cjhopman, 2015-02-20 20:28:20]

lgtm

https://codereview.chromium.org/946683002/diff/1/build/config/BUILDCONFIG.gn
File build/config/BUILDCONFIG.gn (left):

https://codereview.chromium.org/946683002/diff/1/build/config/BUILDCONFIG.gn#...
build/config/BUILDCONFIG.gn:120: target_arch = "arm"
On 2015/02/20 20:06:50, Dirk Pranke wrote:
> I think it's perhaps best to just cut straight to getting users to specify
> target_cpu instead of target_arch, if they need to do an x86 android build (or
> some other variant). I'm not even sure if any non-arm Android build actually
> works at the moment, so I don't know if anyone is actually using non-arm
values,
> 
> 
> It would not be hard to support target_arch for backwards compatibility for
some
> time, though, if that would be preferred.

Make them use target_cpu sgtm.

[Dirk Pranke, 2015-02-20 22:05:13]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2015-02-20 22:06:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/946683002/1

[commit-bot: I haz the power, 2015-02-20 22:10:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-20 22:10:56]

Patchset 1 (id:??) landed as
https://crrev.com/55187fbe2d3264d4c31432e2f8a77f094d7c986b
Cr-Commit-Position: refs/heads/master@{#317419}