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

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

Index: mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.cc
diff --git a/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.cc b/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.cc
index 700368e83eaee928a7e4cba14e26fb03ecb734b0..038aab2b989f2837da0a188ca8e0fb646c20e844 100644
--- a/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.cc
+++ b/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.cc
@@ -7,17 +7,40 @@
 namespace mojo {
 
 // static
+bool StructTraits<test::StructWithTraitsElement,
+                  test::StructWithTraitsElementImpl>::
+    Read(test::StructWithTraitsElementDataView data,
+         test::StructWithTraitsElementImpl* 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_string2);
+
+  if (!data.ReadFArrayString(&out->get_mutable_array_string()))
     return false;
-  out->set_string(f_string.as_string());
-  return f_string == f_string2;
+
+  if (!data.ReadFElement(&out->get_mutable_element()))
+    return false;
+
+  if (!data.ReadFArrayElement(&out->get_mutable_array_element()))
+    return false;
+
+  return true;
 }
 
 }  // namespace mojo