[NaCl SDK] Add ppapi_stub for bionic

[NaCl SDK} Add ppapi_stub for bionic

Bionic uses a different loader which requires a different ppapi_stub.
This implementaion is for the experimental bionic build only.

BUG=none
R=binji@chromium.org

See related issue to re-merge with GYP/GN
https://code.google.com/p/chromium/issues/detail?id=368779

[noelallen1, 2014-04-30 18:50:40]

ptal

Based on src/ppapi/native_client/src/untrusted/irt_stub

[Sam Clegg, 2014-04-30 19:05:56]

On 2014/04/30 18:50:40, noelallen1 wrote:
> ptal
> 
> Based on src/ppapi/native_client/src/untrusted/irt_stub

Why use a whole different build mechanism?   Maybe because untrusted.gypi
doesn't support bionic yet?  Perhaps add comments with explanation and TODO to
integrate back to ppapi/native_client/src/untrusted/irt_stub?

[noelallen1, 2014-04-30 19:55:49]

On 2014/04/30 19:05:56, Sam Clegg wrote:
> On 2014/04/30 18:50:40, noelallen1 wrote:
> > ptal
> > 
> > Based on src/ppapi/native_client/src/untrusted/irt_stub
> 
> Why use a whole different build mechanism?   Maybe because untrusted.gypi
> doesn't support bionic yet?  Perhaps add comments with explanation and TODO to
> integrate back to ppapi/native_client/src/untrusted/irt_stub?

Correct, filed:
https://code.google.com/p/chromium/issues/detail?id=368779

[binji, 2014-04-30 23:54:36]

On 2014/04/30 19:55:49, noelallen1 wrote:
> On 2014/04/30 19:05:56, Sam Clegg wrote:
> > On 2014/04/30 18:50:40, noelallen1 wrote:
> > > ptal
> > > 
> > > Based on src/ppapi/native_client/src/untrusted/irt_stub
> > 
> > Why use a whole different build mechanism?   Maybe because untrusted.gypi
> > doesn't support bionic yet?  Perhaps add comments with explanation and TODO
to
> > integrate back to ppapi/native_client/src/untrusted/irt_stub?
> 
> Correct, filed:
> https://code.google.com/p/chromium/issues/detail?id=368779

Why copy paste rather than using the files directly?

[noelallen1, 2014-05-01 16:36:05]

Several reasons, the version in chrome:
  uses chrome relative headers and include paths.
  can affect chrome build/test, the private one won't.
  this really belongs in the SDK, but it's needed for chrome testing.

[binji, 2014-05-01 16:49:43]

lgtm