Releasing the former Stadia file transfer tools

The tools allow efficient and fast synchronization of large directory
trees from a Windows workstation to a Linux target machine.

cdc_rsync* support efficient copy of files by using content-defined
chunking (CDC) to identify chunks within files that can be reused.

asset_stream_manager + cdc_fuse_fs support efficient streaming of a
local directory to a remote virtual file system based on FUSE. It also
employs CDC to identify and reuse unchanged data chunks.

common/test_main.cc

@@ -0,0 +1,53 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "common/path.h"
+#include "gtest/gtest.h"
+#include "tools/cpp/runfiles/runfiles.h"
+
+using bazel::tools::cpp::runfiles::Runfiles;
+
+namespace cdc_ft {
+namespace {
+Runfiles* runfiles_ptr;
+}
+
+std::string GetTestDataDir(const char* test_data_dir) {
+  std::string test_path =
+      ::testing::UnitTest::GetInstance()->current_test_info()->file();
+  std::string test_dir = path::DirName(test_path);
+  std::string root_runfile = path::ToUnix(
+      path::Join("cdc_file_transfer", test_dir, "testdata", "root.txt"));
+  assert(runfiles_ptr != nullptr);
+  std::string root_path = runfiles_ptr->Rlocation(root_runfile);
+  path::FixPathSeparators(&root_path);
+  EXPECT_TRUE(path::Exists(root_path))
+      << path::Join(test_dir, "testdata") << " directory has no root.txt file";
+  return path::Join(path::DirName(root_path), test_data_dir);
+}
+
+}  // namespace cdc_ft
+
+int main(int argc, char** argv) {
+  std::string error;
+  std::unique_ptr<Runfiles> runfiles(Runfiles::Create(argv[0], &error));
+  if (runfiles == nullptr) {
+    std::cerr << "Failed to locate runtime files: " << error << std::endl;
+    return 1;
+  }
+  cdc_ft::runfiles_ptr = runfiles.get();
+
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}