Update Chomium's build files to work w/ latest GN binaries.

Update Chomium's build files to work w/ latest GN binaries.

The latest GN binaries rename cpu_arch to current_cpu and/or target_cpu
as appropriate, build_cpu_arch to host_cpu, and os to current_os and target_os as appropriate.

R=brettw@chromium.org
TBR=ddorwin@chromium.org
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
BUG=344767
Committed: https://crrev.com/4327621a322c964a8bc6d1ef5a4534f0f877d63e
Cr-Commit-Position: refs/heads/master@{#317223}

[Dirk Pranke, 2015-02-12 03:02:19]

Patchset #1 (id:1) has been deleted

[brettw, 2015-02-12 18:04:32]

LGTM

https://codereview.chromium.org/913373002/diff/20001/ppapi/BUILD.gn
File ppapi/BUILD.gn (right):

https://codereview.chromium.org/913373002/diff/20001/ppapi/BUILD.gn#newcode392
ppapi/BUILD.gn:392: if (is_win && current_cpu == "x64" && current_toolchain !=
default_toolchain) {
Seems like you need to run "gn format" on this change.

[Dirk Pranke, 2015-02-19 00:10:56]

New patchsets have been uploaded after l-g-t-m from brettw@chromium.org

[Dirk Pranke, 2015-02-19 00:18:31]

This patch depends on https://codereview.chromium.org/936103003/ landing first
...

[Dirk Pranke, 2015-02-20 02:34:54]

dpranke@chromium.org changed reviewers:
+ ddorwin@chromium.org

[Dirk Pranke, 2015-02-20 02:35:03]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2015-02-20 02:35:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/913373002/80001

[ddorwin, 2015-02-20 02:47:08]

https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
File third_party/widevine/cdm/BUILD.gn (right):

https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
third_party/widevine/cdm/BUILD.gn:5: widevine_arch = current_cpu
The description says "current_cpu_arch", but multiple files appear to just use
"current_cpu".

[Dirk Pranke, 2015-02-20 02:47:42]

On 2015/02/20 02:47:08, ddorwin wrote:
>
https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
> File third_party/widevine/cdm/BUILD.gn (right):
> 
>
https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
> third_party/widevine/cdm/BUILD.gn:5: widevine_arch = current_cpu
> The description says "current_cpu_arch", but multiple files appear to just use
> "current_cpu".

Ah, good catch. It should be 'current_cpu'. Will fix.

[ddorwin, 2015-02-20 02:53:35]

third_party/widevine/cdm/ LGTM, though I can't say whether it should be
current_cpu or target_cpu.

https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
File third_party/widevine/cdm/BUILD.gn (right):

https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
third_party/widevine/cdm/BUILD.gn:5: widevine_arch = current_cpu
What is the difference between current_cpu and target_cpu? It sounds like
neither are the host so either would work here.

[commit-bot: I haz the power, 2015-02-20 02:55:32]

Committed patchset #4 (id:80001)

[commit-bot: I haz the power, 2015-02-20 02:56:19]

Patchset 4 (id:??) landed as
https://crrev.com/4327621a322c964a8bc6d1ef5a4534f0f877d63e
Cr-Commit-Position: refs/heads/master@{#317223}

[Dirk Pranke, 2015-02-20 03:00:26]

https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
File third_party/widevine/cdm/BUILD.gn (right):

https://codereview.chromium.org/913373002/diff/80001/third_party/widevine/cdm...
third_party/widevine/cdm/BUILD.gn:5: widevine_arch = current_cpu
On 2015/02/20 02:53:35, ddorwin wrote:
> What is the difference between current_cpu and target_cpu? It sounds like
> neither are the host so either would work here.

generally you want current_cpu (the cpu of the current toolchain).

Probably the only time you want to look at target_cpu instead is if you're
building something on one architecture (usually the host) but what you build
depends on what the target will ultimately be. V8 has this, where they
precompile some JS on the host but how they precompile it varies.