Use macros to define pepper interfaces

ppapi/proxy/ppb_buffer_proxy.h

Index: ppapi/proxy/ppb_buffer_proxy.h
diff --git a/ppapi/proxy/ppb_buffer_proxy.h b/ppapi/proxy/ppb_buffer_proxy.h
index 2c0b875a2735b3ecae1fee45c1709d9b6b43fdff..4105dccfbfb0bbbd40d4f07328b0d904f2751c2b 100644
--- a/ppapi/proxy/ppb_buffer_proxy.h
+++ b/ppapi/proxy/ppb_buffer_proxy.h
@@ -46,24 +46,20 @@ class Buffer : public thunk::PPB_Buffer_API, public Resource {
 
 class PPB_Buffer_Proxy : public InterfaceProxy {
  public:
-  PPB_Buffer_Proxy(Dispatcher* dispatcher, const void* target_interface);
+  PPB_Buffer_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_Buffer_Proxy();
 
-  static const Info* GetInfo();
-
   static PP_Resource CreateProxyResource(PP_Instance instance,
                                          uint32_t size);
   static PP_Resource AddProxyResource(const HostResource& resource,
                                       base::SharedMemoryHandle shm_handle,
                                       uint32_t size);
 
-  const PPB_Buffer_Dev* ppb_buffer_target() const {
-    return static_cast<const PPB_Buffer_Dev*>(target_interface());
-  }
-
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
+  static const InterfaceID kInterfaceID = INTERFACE_ID_PPB_BUFFER;
+
  private:
   // Message handlers.
   void OnMsgCreate(PP_Instance instance,