[Not for commit] Test performance impact if string validation checks whether it is utf8.

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

Index: mojo/public/cpp/bindings/lib/serialization.h
diff --git a/mojo/public/cpp/bindings/lib/serialization.h b/mojo/public/cpp/bindings/lib/serialization.h
index 359b02b77c25a55636560bb7d94f28e28a0bf702..409e07213d1b9b393bebf318d08501e825389305 100644
--- a/mojo/public/cpp/bindings/lib/serialization.h
+++ b/mojo/public/cpp/bindings/lib/serialization.h
@@ -7,6 +7,7 @@
 
 #include <string.h>
 
+#include "base/strings/string_util.h"
 #include "mojo/public/cpp/bindings/array_traits_carray.h"
 #include "mojo/public/cpp/bindings/array_traits_stl.h"
 #include "mojo/public/cpp/bindings/lib/array_serialization.h"
@@ -25,6 +26,77 @@
 namespace mojo {
 namespace internal {
 
+inline std::vector<uint8_t> SerializeString(const std::string& value) {
+  SerializationContext context;
+  size_t size = PrepareToSerialize<StringDataView>(value, &context);
+  DCHECK_EQ(size, Align(size));
+
+  std::vector<uint8_t> result(size);
+  if (size == 0)
+    return result;
+
+  void* result_buffer = &result.front();
+  // The serialization logic requires that the buffer is 8-byte aligned. If the
+  // result buffer is not properly aligned, we have to do an extra copy. In
+  // practice, this should never happen for std::vector.
+  bool need_copy = !IsAligned(result_buffer);
+
+  if (need_copy) {
+    // calloc sets the memory to all zero.
+    result_buffer = calloc(size, 1);
+    DCHECK(IsAligned(result_buffer));
+  }
+
+  Buffer buffer;
+  buffer.Initialize(result_buffer, size);
+  typename MojomTypeTraits<StringDataView>::Data* data = nullptr;
+  Serialize<StringDataView>(value, &buffer, &data, &context);
+
+  if (need_copy) {
+    memcpy(&result.front(), result_buffer, size);
+    free(result_buffer);
+  }
+
+  return result;
+}
+
+inline bool DeserializeString(bool utf8_check,
+                              const std::vector<uint8_t>& input,
+                              std::string* output) {
+  using DataType = MojomTypeTraits<StringDataView>::Data;
+
+  void* input_buffer =
+      input.size() == 0
+          ? nullptr
+          : const_cast<void*>(reinterpret_cast<const void*>(&input.front()));
+
+  // Please see comments in StructSerializeImpl.
+  bool need_copy = !IsAligned(input_buffer);
+
+  if (need_copy) {
+    input_buffer = malloc(input.size());
+    DCHECK(IsAligned(input_buffer));
+    memcpy(input_buffer, &input.front(), input.size());
+  }
+
+  ValidationContext validation_context(input_buffer, input.size(), 0, 0);
+  ContainerValidateParams params(0, false, nullptr);
+  bool result = false;
+  if (DataType::Validate(input_buffer, &validation_context, &params)) {
+    DataType* data = reinterpret_cast<DataType*>(input_buffer);
+    base::StringPiece string_piece(data->storage(), data->size());
+    if (!utf8_check || base::IsStringUTF8(string_piece)) {
+      SerializationContext context;
+      result = Deserialize<StringDataView>(data, output, &context);
+    }
+  }
+
+  if (need_copy)
+    free(input_buffer);
+
+  return result;
+}
+
 template <typename MojomType, typename DataArrayType, typename UserType>
 DataArrayType StructSerializeImpl(UserType* input) {
   static_assert(BelongsTo<MojomType, MojomTypeCategory::STRUCT>::value,