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.

cdc_rsync/error_messages.h

@@ -0,0 +1,54 @@
+/*
+ * 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.
+ */
+
+#ifndef CDC_RSYNC_ERROR_MESSAGES_H_
+#define CDC_RSYNC_ERROR_MESSAGES_H_
+
+namespace cdc_ft {
+
+// Server connection timed out. SSH probably stale.
+constexpr char kMsgFmtConnectionTimeout[] =
+    "Server connection timed out. Please re-run 'ggp ssh init' and verify that "
+    "the IP '%s' and the port '%i' are correct.";
+
+// Server connection timed out and IP was not passed in. Probably network error.
+constexpr char kMsgConnectionTimeoutWithIp[] =
+    "Server connection timed out. Please check your network connection.";
+
+// Receiving pipe end was shut down unexpectedly.
+constexpr char kMsgConnectionLost[] =
+    "The connection to the instance was shut down unexpectedly.";
+
+// Binding to the port failed.
+constexpr char kMsgAddressInUse[] =
+    "Failed to establish a connection to the instance. All ports are already "
+    "in use. This can happen if another instance of this command is running. "
+    "Currently, only 10 simultaneous connections are supported.";
+
+// Deployment failed even though gamelet components were copied successfully.
+constexpr char kMsgDeployFailed[] =
+    "Failed to deploy the instance components for unknown reasons. "
+    "Please report this issue.";
+
+// Picking an instance is not allowed in quiet mode.
+constexpr char kMsgInstancePickerNotAvailableInQuietMode[] =
+    "Multiple gamelet instances are reserved, but the instance picker is not "
+    "available in quiet mode. Please specify --instance or remove -q resp. "
+    "--quiet.";
+
+}  // namespace cdc_ft
+
+#endif  // CDC_RSYNC_ERROR_MESSAGES_H_