Revert of mojo: Convert gles2 to the new thunking system

mojo/public/platform/native/system_thunks.cc

Index: mojo/public/platform/native/system_thunks.cc
diff --git a/mojo/public/platform/native/system_thunks.cc b/mojo/public/platform/native/system_thunks.cc
index fed6db9d9b981e1bc9450074ce2542104c033438..6fdc4f4530ff0af9c6205c6e02d4e92c0add2061 100644
--- a/mojo/public/platform/native/system_thunks.cc
+++ b/mojo/public/platform/native/system_thunks.cc
@@ -5,8 +5,6 @@
 #include "mojo/public/platform/native/system_thunks.h"
 
 #include <assert.h>
-
-#include "mojo/public/platform/native/thunk_export.h"
 
 extern "C" {
 
@@ -154,6 +152,14 @@
   return g_thunks.UnmapBuffer(buffer);
 }
 
+// Call this function by looking
+// Always export this api.
+#if defined(WIN32)
+#define THUNK_EXPORT __declspec(dllexport)
+#else
+#define THUNK_EXPORT __attribute__((visibility("default")))
+#endif
+
 extern "C" THUNK_EXPORT size_t MojoSetSystemThunks(
     const MojoSystemThunks* system_thunks) {
   if (system_thunks->size >= sizeof(g_thunks))