PPAPI: Implement PPB_FileMapping on POSIX

ppapi/proxy/ppb_instance_proxy.cc

Index: ppapi/proxy/ppb_instance_proxy.cc
diff --git a/ppapi/proxy/ppb_instance_proxy.cc b/ppapi/proxy/ppb_instance_proxy.cc
index 6429f50d3a7298423ac87bf631c9f7ea84e8e5a4..80715ada31fcc045df84229a95aa3fdfcf786be0 100644
--- a/ppapi/proxy/ppb_instance_proxy.cc
+++ b/ppapi/proxy/ppb_instance_proxy.cc
@@ -19,6 +19,7 @@
 #include "ppapi/proxy/content_decryptor_private_serializer.h"
 #include "ppapi/proxy/enter_proxy.h"
 #include "ppapi/proxy/extensions_common_resource.h"
+#include "ppapi/proxy/file_mapping_resource.h"
 #include "ppapi/proxy/flash_clipboard_resource.h"
 #include "ppapi/proxy/flash_file_resource.h"
 #include "ppapi/proxy/flash_fullscreen_resource.h"
@@ -363,6 +364,9 @@ Resource* PPB_Instance_Proxy::GetSingletonResource(PP_Instance instance,
     case EXTENSIONS_COMMON_SINGLETON_ID:
       new_singleton = new ExtensionsCommonResource(connection, instance);
       break;
+    case FILE_MAPPING_SINGLETON_ID:
+      new_singleton = new FileMappingResource(connection, instance);
+      break;
     case GAMEPAD_SINGLETON_ID:
       new_singleton = new GamepadResource(connection, instance);
       break;