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

mojo/public/cpp/bindings/array_traits_stl.h

 // Copyright 2016 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.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_ARRAY_TRAITS_STL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_ARRAY_TRAITS_STL_H_
 
 #include <vector>
 
 #include "mojo/public/cpp/bindings/array_traits.h"
@@ skipping 25 matching lines @@
     return input[index];
   }
 
   static typename std::vector<T>::const_reference GetAt(
       const std::vector<T>& input,
       size_t index) {
     return input[index];
   }
 
   static bool Resize(std::vector<T>& input, size_t size) {
-    input.resize(size);
+    if (input.size() != size) {
+      // This is a hack to make compilers for Mac and Android happy. They
+      // currently don't allow resizing types like
+      // std::vector<std::vector<MoveOnlyType>>.
+      // Because the deserialization code doesn't care about the original
+      // contents of |input|, we discard them directly.
+      std::vector<T> temp(size);
+      input.swap(temp);
+    }
+
     return true;
   }
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ARRAY_TRAITS_STL_H_