Use macros to define pepper interfaces

ppapi/proxy/ppb_font_proxy.h

Index: ppapi/proxy/ppb_font_proxy.h
diff --git a/ppapi/proxy/ppb_font_proxy.h b/ppapi/proxy/ppb_font_proxy.h
index c9807e2fdfa3c46b3dd033b68173892adb4a1ae8..d7af48553241e97c6c182ea4676e42fd647edcc6 100644
--- a/ppapi/proxy/ppb_font_proxy.h
+++ b/ppapi/proxy/ppb_font_proxy.h
@@ -21,15 +21,12 @@ namespace proxy {
 
 class SerializedVarReturnValue;
 
-class PPB_Font_Proxy : public ppapi::FunctionGroupBase,
-                       public ppapi::thunk::PPB_Font_FunctionAPI,
-                       public InterfaceProxy {
+class PPB_Font_Proxy : public InterfaceProxy,
+                       public ppapi::thunk::PPB_Font_FunctionAPI {
  public:
-  PPB_Font_Proxy(Dispatcher* dispatcher, const void* target_interface);
+  PPB_Font_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_Font_Proxy();
 
-  static const Info* GetInfo();
-
   // FunctionGroupBase overrides.
   virtual ppapi::thunk::PPB_Font_FunctionAPI* AsPPB_Font_FunctionAPI() OVERRIDE;
 
@@ -39,6 +36,8 @@ class PPB_Font_Proxy : public ppapi::FunctionGroupBase,
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
 
+  static const InterfaceID kInterfaceID = INTERFACE_ID_PPB_FONT;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(PPB_Font_Proxy);
 };