Use macros to define pepper interfaces

ppapi/proxy/ppb_file_system_proxy.h

Index: ppapi/proxy/ppb_file_system_proxy.h
diff --git a/ppapi/proxy/ppb_file_system_proxy.h b/ppapi/proxy/ppb_file_system_proxy.h
index b83fb992932ea40bc416f6593d7bb9e6bc6cec9c..5573cce5d9ab6b04299af70dfbabefb78a59b1a0 100644
--- a/ppapi/proxy/ppb_file_system_proxy.h
+++ b/ppapi/proxy/ppb_file_system_proxy.h
@@ -26,7 +26,7 @@ namespace proxy {
 
 class PPB_FileSystem_Proxy : public InterfaceProxy {
  public:
-  PPB_FileSystem_Proxy(Dispatcher* dispatcher, const void* target_interface);
+  PPB_FileSystem_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_FileSystem_Proxy();
 
   static const Info* GetInfo();
@@ -37,6 +37,8 @@ class PPB_FileSystem_Proxy : public InterfaceProxy {
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
+  static const InterfaceID kInterfaceID = INTERFACE_ID_PPB_FILE_SYSTEM;
+
  private:
   // Message handlers.
   void OnMsgCreate(PP_Instance instance,