Split the PNaCl IRT shim into 3 pieces, and include one piece into IRT.

ppapi/native_client/src/untrusted/pnacl_irt_shim/pnacl_irt_shim.gyp

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'includes': [
     '../../../../../native_client/build/untrusted.gypi',
   ],
   'targets': [
     {
-      'target_name': 'pnacl_irt_shim',
+      # The full library, which PNaCl uses for offline .pexe -> .nexe.
+      'target_name': 'pnacl_irt_shim_aot',
       'type': 'none',
       'variables': {
         'nlib_target': 'libpnacl_irt_shim.a',
         'out_pnacl_newlib_arm': '>(tc_lib_dir_pnacl_translate)/lib-arm/>(nlib_target)',
         'out_pnacl_newlib_x86_32': '>(tc_lib_dir_pnacl_translate)/lib-x86-32/>(nlib_target)',
         'out_pnacl_newlib_x86_64': '>(tc_lib_dir_pnacl_translate)/lib-x86-64/>(nlib_target)',
         'out_pnacl_newlib_mips': '>(tc_lib_dir_pnacl_translate)/lib-mips32/>(nlib_target)',
         'build_glibc': 0,
         'build_newlib': 0,
         'build_pnacl_newlib': 1,
         'pnacl_native_biased': 1,
         'enable_x86_32': 1,
         'enable_x86_64': 1,
         'enable_arm': 1,
         'enable_mips': 1,
         'sources': [
+          'irt_shim_ppapi.c',
           'pnacl_shim.c',
           'shim_entry.c',
           'shim_ppapi.c',
         ],
         'extra_args': [
           '--strip-debug',
         ],
+        # Indicate that shim should not depend on unstable IRT hook interface.
+        'compile_flags': [
+          '-DPNACL_SHIM_AOT',
+        ],
+      },
+      'dependencies': [
+        '<(DEPTH)/native_client/tools.gyp:prep_toolchain',
+      ],
+    },
+    # Smaller shim library for PNaCl in-browser translation.
+    # Uses an unstable IRT hook interface to get the shim from the IRT itself.
+    # If we ever change that hook interface or change the in-IRT shim's ABI,
+    # we would need to clear the translation cache to match the new IRT.
+    {
+      'target_name': 'pnacl_irt_shim_browser',
+      'type': 'none',
+      'variables': {
+        # Same name as pnacl_irt_shim_aot, so that we don't need to change
+        # the linker commandlines, but output to the "for_browser" directory,
+        # and have the pnacl_support_extension copy from that directory.
+        'nlib_target': 'libpnacl_irt_shim.a',
+        'out_pnacl_newlib_arm': '>(tc_lib_dir_pnacl_translate)/lib-arm/for_browser/>(nlib_target)',
+        'out_pnacl_newlib_x86_32': '>(tc_lib_dir_pnacl_translate)/lib-x86-32/for_browser/>(nlib_target)',
+        'out_pnacl_newlib_x86_64': '>(tc_lib_dir_pnacl_translate)/lib-x86-64/for_browser/>(nlib_target)',
+        'out_pnacl_newlib_mips': '>(tc_lib_dir_pnacl_translate)/lib-mips32/for_browser/>(nlib_target)',
+        'build_glibc': 0,
+        'build_newlib': 0,
+        'build_pnacl_newlib': 1,
+        'pnacl_native_biased': 1,
+        'enable_x86_32': 1,
+        'enable_x86_64': 1,
+        'enable_arm': 1,
+        'enable_mips': 1,
+        'sources': [
+          'shim_entry.c',
+          'shim_ppapi.c',
+        ],
+        'extra_args': [
+          '--strip-debug',
+        ],
       },
       'dependencies': [
         '<(DEPTH)/native_client/tools.gyp:prep_toolchain',
+      ],
+    },
+    {
+      # Second half of shim library for PNaCl in-browser translation.
+      # This half goes into the IRT and is returned by the unstable
+      # IRT hook interface.
+      'target_name': 'pnacl_irt_shim_for_irt',
+      'type': 'none',
+      'variables': {
+        'nlib_target': 'libpnacl_irt_shim_for_irt.a',
+        'build_glibc': 0,
+        'build_newlib': 0,
+        # Unlike the above, build this the way the IRT is built so that the
+        # output library directories match the IRT linking search paths.
+        'build_irt': 1,
+        'sources': [
+          'irt_shim_ppapi.c',
+          'pnacl_shim.c',
+        ],
+      },
+      'dependencies': [
+        '<(DEPTH)/native_client/tools.gyp:prep_toolchain',
       ],
     },
   ],
 }