Add the concept of a V8 extras exports object

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 910279b52e6b29828a87e25106dde376aecc4869..5227073759677071a8421544874c1b99eb931d40 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -6371,6 +6371,12 @@ class V8_EXPORT Context {
   V8_INLINE Local<Value> GetEmbedderData(int index);
 
   /**
+   * Gets the exports object used by V8 extras. Extra natives get a reference
+   * to this object and can use it to export functionality.
+   */
+  Local<Object> GetExtrasExportsObject();
+
+  /**
    * Sets the embedder data with the given index, growing the data as
    * needed. Note that index 0 currently has a special meaning for Chrome's
    * debugger.