Make //mojo/edk/js a component.

mojo/edk/js/js_export.h

Index: mojo/edk/js/js_export.h
diff --git a/mojo/edk/js/js_export.h b/mojo/edk/js/js_export.h
new file mode 100644
index 0000000000000000000000000000000000000000..179113ce4fe04cbf3239b36e83a2bfe1837e39ae
--- /dev/null
+++ b/mojo/edk/js/js_export.h
@@ -0,0 +1,32 @@
+// Copyright 2016 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.
+
+#ifndef MOJO_EDK_JS_JS_EXPORT_H_
+#define MOJO_EDK_JS_JS_EXPORT_H_
+
+// Defines MOJO_JS_EXPORT so that functionality implemented by //mojo/edk/js can
+// be exported to consumers.
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(MOJO_JS_IMPLEMENTATION)
+#define MOJO_JS_EXPORT __declspec(dllexport)
+#else
+#define MOJO_JS_EXPORT __declspec(dllimport)
+#endif  // defined(MOJO_JS_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(MOJO_JS_IMPLEMENTATION)
+#define MOJO_JS_EXPORT __attribute__((visibility("default")))
+#else
+#define MOJO_JS_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define MOJO_JS_EXPORT
+#endif
+
+#endif  // MOJO_EDK_JS_JS_EXPORT_H_