Mojo C++ bindings: add a new mode to generator to use native STL/WTF types

mojo/public/cpp/bindings/map.h

Index: mojo/public/cpp/bindings/map.h
diff --git a/mojo/public/cpp/bindings/map.h b/mojo/public/cpp/bindings/map.h
index 8fa3d6708dd13241d32014c7f64697e850371f21..d4c79525ee83c47ce9749fbab68bf9781c4dab3e 100644
--- a/mojo/public/cpp/bindings/map.h
+++ b/mojo/public/cpp/bindings/map.h
@@ -7,6 +7,7 @@
 
 #include <stddef.h>
 #include <map>
+#include <unordered_map>
 #include <utility>
 
 #include "base/logging.h"
@@ -135,14 +136,13 @@ class Map {
   const std::map<Key, Value>& storage() const { return map_; }
 
   // Passes the underlying storage and resets this map to null.
-  //
-  // TODO(yzshen): Consider changing this to a rvalue-ref-qualified conversion
-  // to std::map<Key, Value> after we move to MSVC 2015.
   std::map<Key, Value> PassStorage() {
     is_null_ = true;
     return std::move(map_);
   }
 
+  operator const std::map<Key, Value>&() const { return map_; }
+
   // Swaps the contents of this Map with another Map of the same type (including
   // nullness).
   void Swap(Map<Key, Value>* other) {