Workaround assembly offsets build error for WebRTC standalone.

Workaround assembly offsets build error for WebRTC standalone.

This enables the new build WebRTC is moving to as a result of
the Chromium Git switch in https://webrtc-codereview.appspot.com/16229005/

Without this compilation fails like this (manually linewrapped):

[209/2563] ACTION gen_asm_offsets_vp8: unpack_lib_posix_655f0f79285c2909a9158512344a42a2
FAILED: cd ../../chromium/src/third_party/libvpx;
../../../../third_party/libvpx/unpack_lib_posix.sh
-d ../../../../out/Release/obj/chromium/src/third_party/libvpx/gen_asm_offsets_vp8.gen
-f vp8_asm_enc_offsets.o
-a ../../../../out/Release/libvpx_asm_offsets_vp8.a
-a ../../../../out/Release/obj/third_party/libvpx/libvpx_asm_offsets_vp8.a
-a ../../../../out/Release/obj/Source/WebKit/chromium/third_party/libvpx/libvpx_asm_offsets_vp8.a
-a ""
Failed to locate a static library.

In the current setup, the static library files are put in
<(LIB_DIR)/third_party/libvpx
but after https://webrtc-codereview.appspot.com/16229005/ they
end up in <(LIB_DIR)/chromium/src/third_party/libvpx instead
(caused by the fact that we're now symlinking into Chromium's libvpx
folder instead).

I assume adding another line to fix our problem won't cause any side-effects?

BUG=webrtc:2863, chromium:339647
TEST=Passing local build with https://webrtc-codereview.appspot.com/16229005/ and this patch applied.
R=tomfinegan@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288724

[kjellander_chromium, 2014-08-08 11:11:15]

Frank/Robbie: main review since you have more context.
Tom: owner rubberstamp.

[iannucci, 2014-08-08 15:29:55]

On 2014/08/08 11:11:15, kjellander wrote:
> Frank/Robbie: main review since you have more context.
> Tom: owner rubberstamp.

Hm, I can't actually trigger trybots on this CL, but it would be enlightening to
have mac_chromium_rel, linux_chromium_rel, and win_chromium_rel trybot results.

[iannucci, 2014-08-08 15:30:20]

On 2014/08/08 15:29:55, iannucci wrote:
> On 2014/08/08 11:11:15, kjellander wrote:
> > Frank/Robbie: main review since you have more context.
> > Tom: owner rubberstamp.
> 
> Hm, I can't actually trigger trybots on this CL, but it would be enlightening
to
> have mac_chromium_rel, linux_chromium_rel, and win_chromium_rel trybot
results.

Oh, wait, this is against
svn:/​/​svn.chromium.org/​chrome/​trunk/​deps/​third_party/​libvpx/​ . derp :/

[Tom Finegan, 2014-08-09 02:09:48]

On 2014/08/08 15:30:20, iannucci wrote:
> On 2014/08/08 15:29:55, iannucci wrote:
> > On 2014/08/08 11:11:15, kjellander wrote:
> > > Frank/Robbie: main review since you have more context.
> > > Tom: owner rubberstamp.
> > 
> > Hm, I can't actually trigger trybots on this CL, but it would be
enlightening
> to
> > have mac_chromium_rel, linux_chromium_rel, and win_chromium_rel trybot
> results.
> 
> Oh, wait, this is against
> svn:/​/​svn.chromium.org/​chrome/​trunk/​deps/​third_party/​libvpx/​ . derp :/

lgtm

Add all the paths!

[kjellander_chromium, 2014-08-11 16:23:38]

On 2014/08/08 15:30:20, iannucci wrote:
> On 2014/08/08 15:29:55, iannucci wrote:
> > On 2014/08/08 11:11:15, kjellander wrote:
> > > Frank/Robbie: main review since you have more context.
> > > Tom: owner rubberstamp.
> > 
> > Hm, I can't actually trigger trybots on this CL, but it would be
enlightening
> to
> > have mac_chromium_rel, linux_chromium_rel, and win_chromium_rel trybot
> results.
> 
> Oh, wait, this is against
> svn:/​/​svn.chromium.org/​chrome/​trunk/​deps/​third_party/​libvpx/​ . derp :/

Yeah, it seems it's not possible to run try jobs for this repo today (I looked
at earlier CLs and they were all manually submitted).

[kjellander_chromium, 2014-08-11 16:24:20]

Committed patchset #1 manually as r288724 (presubmit successful).