Push bleeding_edge revisions 2004 and 2006 to trunk....

include/v8.h

Index: include/v8.h
===================================================================
--- include/v8.h	(revision 2010)
+++ include/v8.h	(working copy)
@@ -2246,6 +2246,13 @@
   static Local<Context> GetCurrent();
 
   /**
+   * Returns the context of the calling JavaScript code.  That is the
+   * context of the top-most JavaScript frame.  If there are no
+   * JavaScript frames an empty handle is returned.
+   */
+  static Local<Context> GetCalling();
+
+  /**
    * Sets the security token for the context.  To access an object in
    * another context, the security tokens must match.
    */