[cast_channel] Make cast_channel related files not depend on "cast_channel.h"

components/cast_channel/cast_channel_type.cc

Index: components/cast_channel/cast_channel_type.cc
diff --git a/components/cast_channel/cast_channel_type.cc b/components/cast_channel/cast_channel_type.cc
new file mode 100644
index 0000000000000000000000000000000000000000..65cfaf9564d8288688478988b0f755221d5f2316
--- /dev/null
+++ b/components/cast_channel/cast_channel_type.cc
@@ -0,0 +1,40 @@
+// 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 "components/cast_channel/cast_channel_type.h"
+
+namespace cast_channel {
+
+namespace {
+const char* kReadyStates[] = {"READY_STATE_NONE", "READY_STATE_CONNECTING",
+                              "READY_STATE_OPEN", "READY_STATE_CLOSING",
+                              "READY_STATE_CLOSED"};
+const char* kChannelErrors[] = {"CHANNEL_ERROR_NONE",
+                                "CHANNEL_ERROR_CHANNEL_NOT_OPEN",
+                                "CHANNEL_ERROR_AUTHENTICATION_ERROR",
+                                "CHANNEL_ERROR_CONNECT_ERROR",
+                                "CHANNEL_ERROR_SOCKET_ERROR",
+                                "CHANNEL_ERROR_TRANSPORT_ERROR",
+                                "CHANNEL_ERROR_INVALID_MESSAGE",
+                                "CHANNEL_ERROR_INVALID_CHANNEL_ID",
+                                "CHANNEL_ERROR_CONNECT_TIMEOUT",
+                                "CHANNEL_ERROR_PING_TIMEOUT",
+                                "CHANNEL_ERROR_UNKNOWN"};
+const char* kChannelAuthTypes[] = {"CHANNEL_AUTH_NONE",
+                                   "CHANNEL_AUTH_SSL_VERIFIED"};
+}

[imcheng, 2017/05/24 22:11:23]

}  // namespace

[zhaobin, 2017/05/25 00:49:23]

Code removed.

+
+std::string ToString(ReadyState ready_state) {
+  return kReadyStates[static_cast<int>(ready_state)];

[imcheng, 2017/05/24 22:11:23]

This looks ok, but could be a problem if we added a new value without updating
the array above.

Using a switch statement seems a bit safer. Maybe a macro such as the following
would help with reducing boilerplate, if it's ok to change the string values:
https://cs.corp.google.com/piper///depot/google3/chrome_platform/cast/logging...

It seems we should have some unit tests for these.

[mark a. foltz, 2017/05/24 22:46:36]

If these ToString methods are only for logging, then I'm not sure a unit test is
necessary.  However a switch statement is safer to avoid an out of bounds array
access if values are added.

[zhaobin, 2017/05/25 00:49:22]

Done.

[zhaobin, 2017/05/25 00:49:23]

Done.

+}
+
+std::string ToString(ChannelError channel_error) {
+  return kChannelErrors[static_cast<int>(channel_error)];
+}
+
+std::string ToString(ChannelAuthType channel_auth) {
+  return kChannelAuthTypes[static_cast<int>(channel_auth)];
+}
+
+}  // namespace cast_channel