Add DCHECK for nullptr in gl bindings

ui/gl/generate_bindings.py

Index: ui/gl/generate_bindings.py
diff --git a/ui/gl/generate_bindings.py b/ui/gl/generate_bindings.py
index b3158027a09c3d2b72be8387576c7cbd2aeb766b..1cba075631ad9d3c31440478568f4bc10b74b7f4 100755
--- a/ui/gl/generate_bindings.py
+++ b/ui/gl/generate_bindings.py
@@ -2174,6 +2174,8 @@ void Driver%s::InitializeExtensionBindings() {
     if return_type == 'void':
       file.write('  GL_SERVICE_LOG("%s" << "(" %s << ")");\n' %
           (function_name, log_argument_names))
+      file.write('  DCHECK(g_driver_%s.debug_fn.%sFn != nullptr);\n' %
+          (set_name.lower(), function_name))
       file.write('  g_driver_%s.debug_fn.%sFn(%s);\n' %
           (set_name.lower(), function_name, argument_names))
       if 'logging_code' in func:
@@ -2186,6 +2188,8 @@ void Driver%s::InitializeExtensionBindings() {
     else:
       file.write('  GL_SERVICE_LOG("%s" << "(" %s << ")");\n' %
           (function_name, log_argument_names))
+      file.write('  DCHECK(g_driver_%s.debug_fn.%sFn != nullptr);\n' %
+          (set_name.lower(), function_name))
       file.write('  %s result = g_driver_%s.debug_fn.%sFn(%s);\n' %
           (return_type, set_name.lower(), function_name, argument_names))
       if 'logging_code' in func: