Add target_arch check.

Add target_arch check.

Don't assume target_arch is arm when armv7 is set.

BUG=234135

[Fredrik Öhrn, 2013-04-22 11:22:53]

https://chromiumcodereview.appspot.com/14065005/ changes the default ARM
settings to ARMv7 builds, so the armv7 flag can no longer be used alone.

[digit1, 2013-04-22 12:26:10]

lgtm (not an owner).

Is there a crbug.com entry for this set of changes? If not I suggest creating
one, they help a lot when performing multi-repo patches and DEPS rolls,
especially during sheriffing.

It is already exist, please add a BUG=<number> line at the end of the
description here.

Thanks.

[Fredrik Öhrn, 2013-04-22 12:42:52]

OK, I've now created crbug.com/234135

[DaleCurtis, 2013-04-22 17:56:53]

FFmpeg changes must be submitted through Gerrit:

http://git.chromium.org/gitweb/?p=chromium/third_party/ffmpeg.git;a=blob;f=RE...

There should have been a PRESUBMIT warning for this.  Is it still working?

What values will target_arch have if not arm now?  Do we need do some other
check here to enable arm compilation on these new non-arm target_arch values?

[Fredrik Öhrn, 2013-04-22 18:19:58]

On 2013/04/22 17:56:53, DaleCurtis wrote:
> FFmpeg changes must be submitted through Gerrit:
> 
>
http://git.chromium.org/gitweb/?p=chromium/third_party/ffmpeg.git;a=blob;f=RE...
> 

I see, I'll resubmit in gerrit first thing tomorrow.

> There should have been a PRESUBMIT warning for this.  Is it still working?
> 

It gave a long list of admonitions, but did not mention using gerrit.

> What values will target_arch have if not arm now?  Do we need do some other
> check here to enable arm compilation on these new non-arm target_arch values?

I'm not sure I understand your question. If target_arch != arm (it can be
anything from ia32 to mipsel) the armv7 flag must be ignored since it indicates
a flavor of arm and is not relevant to other CPUs.

[DaleCurtis, 2013-04-22 18:23:42]

Ah, looking, I now see the PRESUBMIT just says use Git, which isn't very
helpful.  I'll fix that when this lands.

Thanks for the explanation.  I thought the change might be adding
target_arch='armvXX' or something.

[Fredrik Öhrn, 2013-04-22 18:45:17]

On 2013/04/22 18:23:42, DaleCurtis wrote:
> Ah, looking, I now see the PRESUBMIT just says use Git, which isn't very
> helpful.  I'll fix that when this lands.
> 

As I'm new here and using the git checkout of Chromium I didn't get the hint. :)

> Thanks for the explanation.  I thought the change might be adding
> target_arch='armvXX' or something.

That's one way of doing it, but the gyp projects are currently geared toward a
single arm architecture that is tuned using additional variables.

I need this fix landed before 14065005 since it changes the defaults, when
everything is in place I'll follow up with another ffmpeg patch to replace armv7
with the new arm_version variable.

[Fredrik Öhrn, 2013-04-23 08:23:59]

Moved to gerrit: https://gerrit.chromium.org/gerrit/48881