Add array bounds assertion and improve type conversion for empty strings.

mojo/public/bindings/lib/bindings_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_BINDINGS_LIB_BINDINGS_INTERNAL_H_
 #define MOJO_PUBLIC_BINDINGS_LIB_BINDINGS_INTERNAL_H_
 
 #include <new>
 
 #include "mojo/public/bindings/lib/buffer.h"
@@ skipping 145 matching lines @@
   static Array_Data<T>* New(size_t num_elements, Buffer* buf) {
     size_t num_bytes = sizeof(Array_Data<T>) +
                        sizeof(StorageType) * num_elements;
     return new (buf->Allocate(num_bytes)) Array_Data<T>(num_bytes,
                                                         num_elements);
   }
 
   size_t size() const { return header_.num_elements; }
 
   T& at(size_t offset) {
+    assert(offset < static_cast<size_t>(header_.num_elements));
     return Traits::ToRef(storage()[offset]);
   }
 
   const T& at(size_t offset) const {
+    assert(offset < static_cast<size_t>(header_.num_elements));
     return Traits::ToConstRef(storage()[offset]);
   }
 
   StorageType* storage() {
     return reinterpret_cast<StorageType*>(
         reinterpret_cast<char*>(this) + sizeof(*this));
   }
 
   const StorageType* storage() const {
     return reinterpret_cast<const StorageType*>(
@@ skipping 40 matching lines @@
     return value;
   }
   static T& ToRef(T& data) { return data; }
   static const T& ToConstRef(const T& data) { return data; }
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_BINDINGS_LIB_BINDINGS_INTERNAL_H_