Convert utility process extension Unpacker IPC to mojo

extensions/test/test_content_browser_client.cc

+// Copyright 2017 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 "extensions/test/test_content_browser_client.h"
+
+#include "base/files/file_util.h"
+#include "base/json/json_reader.h"
+#include "base/path_service.h"
+#include "base/values.h"
+#include "content/public/common/service_names.mojom.h"
+#include "extensions/common/extension_paths.h"
+
+namespace extensions {
+
+TestContentBrowserClient::TestContentBrowserClient() = default;
+
+TestContentBrowserClient::~TestContentBrowserClient() = default;
+
+std::unique_ptr<base::Value>
+TestContentBrowserClient::GetServiceManifestOverlay(base::StringPiece name) {
+  if (name != content::mojom::kUtilityServiceName) {
+    return nullptr;
+  }
+
+  base::FilePath extensions_test_data;
+  if (!base::PathService::Get(DIR_TEST_DATA, &extensions_test_data)) {
+    NOTREACHED();

[Devlin, 2017/02/14 17:24:59]

nit: Given this is test-only code, these may as well be CHECK()s.

[Noel Gordon, 2017/02/15 17:28:09]

Done.

+  }
+
+  std::string content;
+  if (!base::ReadFileToString(
+          extensions_test_data.AppendASCII(
+              "extensions_test_content_utility_manifest_overlay.json"),
+          &content)) {
+    NOTREACHED();
+  }
+
+  return base::JSONReader::Read(content);
+}
+
+}  // namespace extensions