Revert of mojo: Convert gles2 to the new thunking system

mojo/shell/context.cc

Index: mojo/shell/context.cc
diff --git a/mojo/shell/context.cc b/mojo/shell/context.cc
index a97ec489a4b8478f5c3922fd0d9726a4bf653c4d..159e3230d5236cac5a603e8d8ead01ecc935dbf0 100644
--- a/mojo/shell/context.cc
+++ b/mojo/shell/context.cc
@@ -9,6 +9,7 @@
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_vector.h"
 #include "mojo/embedder/embedder.h"
+#include "mojo/gles2/gles2_support_impl.h"
 #include "mojo/public/cpp/application/application_impl.h"
 #include "mojo/service_manager/background_service_loader.h"
 #include "mojo/service_manager/service_loader.h"
@@ -48,6 +49,7 @@
  public:
   Setup() {
     embedder::Init();
+    gles2::GLES2SupportImpl::Init();
   }
 
   ~Setup() {