Mojo cpp bindings: support Clone() for structs and arrays which don't contain handles.

mojo/public/cpp/bindings/lib/array_internal.h

 // Copyright 2013 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_LIB_ARRAY_INTERNAL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_INTERNAL_H_
 
 #include <new>
 #include <vector>
 
@@ skipping 433 matching lines @@
   }
   static inline RefType at(std::vector<T>* vec, size_t offset) {
     return vec->at(offset);
   }
   static inline void Resize(std::vector<T>* vec, size_t size) {
     vec->resize(size);
   }
   static inline void PushBack(std::vector<T>* vec, ForwardType value) {
     vec->push_back(value);
   }
+  static inline void Clone(const std::vector<T>& src_vec,
+                           std::vector<T>* dest_vec) {
+    dest_vec->assign(src_vec.begin(), src_vec.end());
+  }
 };
 
 template <typename T> struct ArrayTraits<T, true> {
   struct StorageType {
     char buf[sizeof(T) + (8 - (sizeof(T) % 8)) % 8];  // Make 8-byte aligned.
   };
   typedef T& RefType;
   typedef const T& ConstRefType;
   typedef T ForwardType;
   static inline void Initialize(std::vector<StorageType>* vec) {
@@ skipping 28 matching lines @@
     if (size <= vec->capacity()) {
       vec->resize(size);
       return;
     }
     std::vector<StorageType> new_storage(size);
     for (size_t i = 0; i < vec->size(); i++)
       new (new_storage.at(i).buf) T(at(vec, i).Pass());
     vec->swap(new_storage);
     Finalize(&new_storage);
   }
+  static inline void Clone(const std::vector<StorageType>& src_vec,
+                           std::vector<StorageType>* dest_vec) {
+    Resize(dest_vec, src_vec.size());
+    for (size_t i = 0; i < src_vec.size(); ++i)
+      at(dest_vec, i) = at(&src_vec, i).Clone();
+  }
 };
 
 template <> struct WrapperTraits<String, false> {
   typedef String_Data* DataType;
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_ARRAY_INTERNAL_H_