NaCl: Move irt_ppapi.{c,h} to the Chromium repo from the NaCl repo

This will allow irt_ppapi.{c,h} to be dropped from the NaCl side.
Until then, there are two copies, and which copy gets linked in will
depend on library search order.

This creates a new directory, ppapi/nacl_irt/, for irt_ppapi.h since
it defines structs that are part of NaCl's stable ABI.  This new
directory is therefore similar to ppapi/c/, but covers how PPAPI is
hooked up in NaCl.  This also avoids any checkdeps problems with
#including from ppapi/proxy/.

I made the following changes to irt_ppapi.{c,h} when moving them:

 * Changed "*" spacing to follow Chromium style.
 * Added a comment for the assignment to "g_is_main_thread".

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3787 
TEST= tested browser_tests with irt_ppapi.c removed from the NaCl side

Review URL: https://codereview.chromium.org/136333013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250319 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ppapi/ppapi_proxy.gypi b/ppapi/ppapi_proxy.gypi
index c37d64e..146cb5b6 100644
--- a/ppapi/ppapi_proxy.gypi
+++ b/ppapi/ppapi_proxy.gypi
@@ -242,6 +242,9 @@
         ],
         'target_conditions': [
           ['>(nacl_untrusted_build)==1', {
+            'sources': [
+              'proxy/irt_ppapi.c',
+            ],
             'sources!': [
               'proxy/audio_input_resource.cc',
               'proxy/broker_dispatcher.cc',