Add GetProcAddress to OpenGL control interface

mojo/gles2/control_thunks_impl.cc

Index: mojo/gles2/control_thunks_impl.cc
diff --git a/mojo/gles2/control_thunks_impl.cc b/mojo/gles2/control_thunks_impl.cc
index 81cad387fbf4f51cd64553fea3d6262de09e9de0..6a1d14dfb5bc3d0013ee2986a417972ecae25ac5 100644
--- a/mojo/gles2/control_thunks_impl.cc
+++ b/mojo/gles2/control_thunks_impl.cc
@@ -7,6 +7,15 @@
 #include "mojo/gles2/gles2_context.h"
 #include "mojo/public/cpp/system/message_pipe.h"
 
+extern "C" {
+
+#define VISIT_GL_CALL(Function, ReturnType, PARAMETERS, ARGUMENTS) \
+  ReturnType MojoGLES2gl##Function PARAMETERS;
+#include "mojo/public/platform/native/gles2/call_visitor.h"
+#undef VISIT_GL_CALL
+
+}
+
 namespace gles2 {
 
 // static
@@ -52,6 +61,15 @@ void ControlThunksImpl::SwapBuffers() {
   current_context_tls_.Get()->interface()->SwapBuffers();
 }
 
+void* ControlThunksImpl::GetProcAddress(const char* name) {
+#define VISIT_GL_CALL(Function, ReturnType, PARAMETERS, ARGUMENTS) \
+  if (!strcmp(name, "gl##Function")) \
+    return reinterpret_cast<void*>(MojoGLES2gl##Function);
+#include "mojo/public/platform/native/gles2/call_visitor.h"
+#undef VISIT_GL_CALL
+  return nullptr;
+}
+
 void* ControlThunksImpl::GetGLES2Interface(MGLContext context) {
   GLES2Context* client = reinterpret_cast<GLES2Context*>(context);
   DCHECK(client);