Relanding this with fixes to the mac dbg builder

ppapi/thunk/ppb_font_api.h

Index: ppapi/thunk/ppb_font_api.h
===================================================================
--- ppapi/thunk/ppb_font_api.h	(revision 118405)
+++ ppapi/thunk/ppb_font_api.h	(working copy)
@@ -7,6 +7,7 @@
 
 #include "ppapi/c/dev/ppb_font_dev.h"
 #include "ppapi/shared_impl/api_id.h"
+#include "ppapi/thunk/ppapi_thunk_export.h"
 
 namespace ppapi {
 namespace thunk {
@@ -22,7 +23,7 @@
 };
 
 // API for font resources.
-class PPB_Font_API {
+class PPAPI_THUNK_EXPORT PPB_Font_API {
  public:
   virtual ~PPB_Font_API() {}