Make IPC::ParamTraits<>GetSize work with base::Value as a result of JSON parsing.

ipc/ipc_message_utils_unittest.cc

 // Copyright (c) 2012 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 "ipc/ipc_message_utils.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/files/file_path.h"
+#include "base/json/json_reader.h"
 #include "ipc/ipc_message.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace IPC {
 namespace {
 
 // Tests nesting of messages as parameters to other messages.
 TEST(IPCMessageUtilsTest, NestedMessages) {
   int32_t nested_routing = 12;
   uint32_t nested_type = 78;
@@ skipping 88 matching lines @@
 
   base::Pickle pickle;
   IPC::WriteParam(&pickle, *value);
 
   base::PickleSizer sizer;
   IPC::GetParamSize(&sizer, *value);
 
   EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
 }
 
+TEST(IPCMessageUtilsTest, JsonValueSize) {
+  const char kJson[] = "[ { \"foo\": \"bar\", \"baz\": 1234.0 } ]";
+  std::unique_ptr<base::Value> json_value = base::JSONReader::Read(kJson);
+  EXPECT_NE(nullptr, json_value);
+  base::ListValue value;
+  value.Append(std::move(json_value));
+
+  base::Pickle pickle;
+  IPC::WriteParam(&pickle, value);
+
+  base::PickleSizer sizer;
+  IPC::GetParamSize(&sizer, value);
+
+  EXPECT_EQ(sizer.payload_size(), pickle.payload_size());
+}
+
 }  // namespace
 }  // namespace IPC