Add a mojoPrivate API that exposes mojo to component apps/extensions.

extensions/common/api/mojo_private.idl

Index: extensions/common/api/mojo_private.idl
diff --git a/extensions/common/api/mojo_private.idl b/extensions/common/api/mojo_private.idl
new file mode 100644
index 0000000000000000000000000000000000000000..083ce638e2ca557e6332393821df9c5d0df8eac6
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+++ b/extensions/common/api/mojo_private.idl
@@ -0,0 +1,19 @@
+// 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.
+
+// The chrome.mojoPrivate API provides access to the mojo modules.
+namespace mojoPrivate {
+
+  // |modules| is an array of the values returned by |dependencies| factories.
+  callback DefineCallback = void (any[] modules);
+
+  interface Functions {
+    // Defines a AMD module.
+    [nocompile] static void define(
+        DOMString moduleName,
+        optional DOMString[] dependencies,
+        DefineCallback factory);
+  };
+
+};