Don't rely on the Android toolchain being exported in the PATH for the {CC,CXX,LINK,AR}_target defi…

Don't rely on the Android toolchain being exported in the PATH for the {CC,CXX,LINK,AR}_target defines.

The make build has start using these environment variables since gyp revision
1470[1]. This works in the Chromium repository as the Android toolchain is being
exported in the PATH, which is something WebKit doesn't do, and we shouldn't
be relying on in general. Instead, use the paths to the toolchain and prefix
them with Android's goma wrapper, which yields the same effect.

[1] https://code.google.com/p/gyp/source/detail?r=1470

BUG=
TEST=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=152340

[Peter Beverloo, 2012-08-20 16:05:47]

Yaron, please take a look. Relying on PATH (again) would break the WebKit
builder (again) when Chromium rolls into WebKit, so I'm hoping no one will do
that today.

I haven't tested this with Ninja. The effect I expect it to have is that the
usage of GOMA will now be mandated if GOMA_DIR is set during project file
generation, whereas this previously could be disabled during build time as well
(by not exporting GOMA in one's path). That seems reasonable to me, though.

[Peter Beverloo, 2012-08-20 16:13:14]

Actually, Ninja doesn't seem to use GOMA with or without this patch. What is the
current status of it?

[Yaron, 2012-08-20 16:42:36]

lgtm

[Yaron, 2012-08-20 16:43:21]

On 2012/08/20 16:42:36, Yaron wrote:
> lgtm

I'm planning to get rid of these variables anyway. To get ninja to use goma you
have to set the GOMA_DIR variable. So I guess in a sense, it still depends on
environment variables but that only needs to be set at gyp time.

[Peter Beverloo, 2012-08-20 16:46:11]

On 2012/08/20 16:43:21, Yaron wrote:
> On 2012/08/20 16:42:36, Yaron wrote:
> > lgtm
> 
> I'm planning to get rid of these variables anyway. To get ninja to use goma
you
> have to set the GOMA_DIR variable. So I guess in a sense, it still depends on
> environment variables but that only needs to be set at gyp time.

Ok, sounds good to me. Thank you, Yaron! I committed this manually so it can
chime in before the NDK r8 roll.