Refactor CastSocket code for the following:

chrome/browser/extensions/api/cast_channel/cast_message_util.cc

 // Copyright 2013 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 "chrome/browser/extensions/api/cast_channel/cast_message_util.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/cast_channel/cast_channel.pb.h"
 #include "chrome/common/extensions/api/cast_channel.h"
 
 namespace {
 static const char kAuthNamespace[] =
     "urn:x-cast:com.google.cast.tp.deviceauth";
 // Sender and receiver IDs to use for platform messages.
 static const char kPlatformSenderId[] = "sender-0";
 static const char kPlatformReceiverId[] = "receiver-0";
 }  // namespace
 
 namespace extensions {
 namespace api {
 namespace cast_channel {
 
 bool MessageInfoToCastMessage(const MessageInfo& message,
                               CastMessage* message_proto) {
   DCHECK(message_proto);
+  if (!message.data)
+    return false;
+
   message_proto->set_protocol_version(CastMessage_ProtocolVersion_CASTV2_1_0);
   message_proto->set_source_id(message.source_id);
   message_proto->set_destination_id(message.destination_id);
   message_proto->set_namespace_(message.namespace_);
   // Determine the type of the base::Value and set the message payload
   // appropriately.
   std::string data;
   base::BinaryValue* real_value;
   switch (message.data->GetType()) {
-  // JS string
-  case base::Value::TYPE_STRING:
-    if (message.data->GetAsString(&data)) {
-      message_proto->set_payload_type(CastMessage_PayloadType_STRING);
-      message_proto->set_payload_utf8(data);
-    }
-    break;
-  // JS ArrayBuffer
-  case base::Value::TYPE_BINARY:
-    real_value = static_cast<base::BinaryValue*>(message.data.get());
-    if (real_value->GetBuffer()) {
-      message_proto->set_payload_type(CastMessage_PayloadType_BINARY);
-      message_proto->set_payload_binary(real_value->GetBuffer(),
-                                        real_value->GetSize());
-    }
-    break;
-  default:
-    // Unknown value type.  message_proto will remain uninitialized because
-    // payload_type is unset.
-    break;
+    // JS string
+    case base::Value::TYPE_STRING:
+      if (message.data->GetAsString(&data)) {
+        message_proto->set_payload_type(CastMessage_PayloadType_STRING);
+        message_proto->set_payload_utf8(data);
+      }
+      break;
+    // JS ArrayBuffer
+    case base::Value::TYPE_BINARY:
+      real_value = static_cast<base::BinaryValue*>(message.data.get());
+      if (real_value->GetBuffer()) {
+        message_proto->set_payload_type(CastMessage_PayloadType_BINARY);
+        message_proto->set_payload_binary(real_value->GetBuffer(),
+                                          real_value->GetSize());
+      }
+      break;
+    default:
+      // Unknown value type.  message_proto will remain uninitialized because
+      // payload_type is unset.
+      break;
   }
   return message_proto->IsInitialized();
 }
 
 bool CastMessageToMessageInfo(const CastMessage& message_proto,
                               MessageInfo* message) {
   DCHECK(message);
   message->source_id = message_proto.source_id();
   message->destination_id = message_proto.destination_id();
   message->namespace_ = message_proto.namespace_();
@@ skipping 69 matching lines @@
   message_proto->set_payload_binary(auth_message_string);
 }
 
 bool IsAuthMessage(const CastMessage& message) {
   return message.namespace_() == kAuthNamespace;
 }
 
 }  // namespace cast_channel
 }  // namespace api
 }  // namespace extensions