Make gn check //mojo/public/* pass

mojo/public/c/gles2/BUILD.gn

Index: mojo/public/c/gles2/BUILD.gn
diff --git a/mojo/public/c/gles2/BUILD.gn b/mojo/public/c/gles2/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..df0007b8b8098c0b2bb49dcaabb1e4a3a3dd2cf5
--- /dev/null
+++ b/mojo/public/c/gles2/BUILD.gn
@@ -0,0 +1,21 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+config("gles2_config") {
+  defines = [ "GLES2_USE_MOJO" ]
+}
+
+source_set("gles2") {
+  sources = [
+    "gles2.h",
+    "gles2_export.h",
+  ]
+
+  public_configs = [ ":gles2_config" ]
+
+  public_deps = [
+    "//mojo/public/c/environment",
+    "//mojo/public/c/system",
+  ]
+}