Push V8 r1767 to trunk. This fixes a problem in the string type...

src/virtual-frame.cc

Index: src/virtual-frame.cc
===================================================================
--- src/virtual-frame.cc	(revision 1761)
+++ src/virtual-frame.cc	(working copy)
@@ -297,6 +297,10 @@
     if (elements_[i].is_copy()) {
       elements_[elements_[i].index()].set_copied();
     }
+
+    // No code needs to be generated to change the static type of an
+    // element.
+    elements_[i].set_static_type(target.static_type());
   }
 }