Mojo C++ bindings: add StringTraits and ArrayTraits for STL types.

mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.cc

 // 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.
 
 #include "mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h"
 
 namespace mojo {
 
 // static
+bool StructTraits<test::NestedStructWithTraits,
+                  test::NestedStructWithTraitsImpl>::
+    Read(test::NestedStructWithTraitsDataView data,
+         test::NestedStructWithTraitsImpl* output) {
+  output->value = data.value();
+  return true;
+}
+
+// static
 bool StructTraits<test::StructWithTraits, test::StructWithTraitsImpl>::Read(
     test::StructWithTraitsDataView data,
     test::StructWithTraitsImpl* out) {
   out->set_bool(data.f_bool());
   out->set_uint32(data.f_uint32());
   out->set_uint64(data.f_uint64());
-  base::StringPiece f_string, f_string2;
-  if (!data.ReadFString(&f_string) || !data.ReadFString2(&f_string2))
+
+  base::StringPiece f_string;
+  std::string f_string2;
+  if (!data.ReadFString(&f_string) || !data.ReadFString2(&f_string2) ||
+      f_string != f_string2) {
     return false;
-  out->set_string(f_string.as_string());
-  return f_string == f_string2;
+  }
+  out->set_string(f_string2);
+
+  if (!data.ReadFStringArray(&out->get_mutable_string_array()))
+    return false;
+
+  if (!data.ReadFStruct(&out->get_mutable_struct()))
+    return false;
+
+  if (!data.ReadFStructArray(&out->get_mutable_struct_array()))
+    return false;
+
+  return true;
 }
 
 }  // namespace mojo