Split apart the PPAPI GN targets

ppapi/cpp/private/BUILD.gn

Index: ppapi/cpp/private/BUILD.gn
diff --git a/testing/legion/__init__.py b/ppapi/cpp/private/BUILD.gn
similarity index 60%
copy from testing/legion/__init__.py
copy to ppapi/cpp/private/BUILD.gn
index 50b23dff631dbfd12f490f20fe2a2871179b73b9..d89644075fae761cebac536cff16ae704121dc99 100644
--- a/testing/legion/__init__.py
+++ b/ppapi/cpp/private/BUILD.gn
@@ -1,3 +1,10 @@
 # Copyright 2015 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.
+# found in the LICENSE file.
+
+source_set("internal_module") {
+  sources = [
+    "internal_module.cc",
+    "internal_module.h",
+  ]
+}