Make component build Chrome link.

ppapi/BUILD.gn

 # Copyright 2014 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.
 
 gypi_values = exec_script(
     "//build/gypi_to_gn.py",
     [ rebase_path("ppapi_sources.gypi") ],
     "scope",
     [ "ppapi_sources.gypi" ])
 
@@ skipping 439 matching lines @@
     "proxy/serialized_flash_menu.h",
     "proxy/serialized_handle.cc",
     "proxy/serialized_handle.h",
     "proxy/serialized_structs.cc",
     "proxy/serialized_structs.h",
     "proxy/serialized_var.cc",
     "proxy/serialized_var.h",
     "proxy/var_serialization_rules.h",
   ]
 
+  defines = [ "PPAPI_PROXY_IMPLEMENTATION" ]
+
   deps = [
     ":ppapi_c",
     ":ppapi_shared",
     "//base",
     "//gpu/ipc",
     "//ipc",
     "//skia",
     "//ui/events/ipc",
   ]
 
@@ skipping 333 matching lines @@
     ":ppapi_shared",
     "//base/test:test_support",
     "//ipc",
     "//ipc:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }
 
 # TODO(GYP) other targets from ppapi_tests.gyp