Do not create a temporary transport channel when using max-bundle

webrtc/pc/channel.cc

Index: webrtc/pc/channel.cc
diff --git a/webrtc/pc/channel.cc b/webrtc/pc/channel.cc
index 7e4d5d2dac1e9596566fc591ef992519616f8594..e3b8fb8f2ba85672d311f013f6cff439a510c775 100644
--- a/webrtc/pc/channel.cc
+++ b/webrtc/pc/channel.cc
@@ -212,8 +212,9 @@ void BaseChannel::DeinitNetwork_n() {
   network_thread_->Clear(this);
 }
 
-bool BaseChannel::Init_w() {
-  if (!network_thread_->Invoke<bool>(Bind(&BaseChannel::InitNetwork_n, this))) {
+bool BaseChannel::Init_w(const std::string* bundle_transport_name) {
+  if (!network_thread_->Invoke<bool>(
+          Bind(&BaseChannel::InitNetwork_n, this, bundle_transport_name))) {
     return false;
   }
 
@@ -224,9 +225,11 @@ bool BaseChannel::Init_w() {
   return true;
 }
 
-bool BaseChannel::InitNetwork_n() {
+bool BaseChannel::InitNetwork_n(const std::string* bundle_transport_name) {
   RTC_DCHECK(network_thread_->IsCurrent());
-  if (!SetTransport_n(content_name())) {
+  const std::string& transport_name =
+      (bundle_transport_name ? *bundle_transport_name : content_name());
+  if (!SetTransport_n(transport_name)) {
     return false;
   }
 
@@ -1454,8 +1457,8 @@ VoiceChannel::~VoiceChannel() {
   Deinit();
 }
 
-bool VoiceChannel::Init_w() {
-  if (!BaseChannel::Init_w()) {
+bool VoiceChannel::Init_w(const std::string* bundle_transport_name) {
+  if (!BaseChannel::Init_w(bundle_transport_name)) {
     return false;
   }
   return true;
@@ -1784,8 +1787,8 @@ VideoChannel::VideoChannel(rtc::Thread* worker_thread,
                   content_name,
                   rtcp) {}
 
-bool VideoChannel::Init_w() {
-  if (!BaseChannel::Init_w()) {
+bool VideoChannel::Init_w(const std::string* bundle_transport_name) {
+  if (!BaseChannel::Init_w(bundle_transport_name)) {
     return false;
   }
   return true;
@@ -2031,8 +2034,8 @@ DataChannel::~DataChannel() {
   Deinit();
 }
 
-bool DataChannel::Init_w() {
-  if (!BaseChannel::Init_w()) {
+bool DataChannel::Init_w(const std::string* bundle_transport_name) {
+  if (!BaseChannel::Init_w(bundle_transport_name)) {
     return false;
   }
   media_channel()->SignalDataReceived.connect(