4 files changed, 26 insertions, 7 deletions
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.h b/src/core/ext/filters/client_channel/client_channel_channelz.h
index 735ffacfd2..5e01fdf2a3 100644
--- a/src/core/ext/filters/client_channel/client_channel_channelz.h
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.h
@@ -77,7 +77,14 @@ class SubchannelNode : public BaseNode {
   grpc_json* RenderJson() override;
 
   // proxy methods to composed classes.
-  ChannelTrace* trace() { return trace_.get(); }
+  void AddTraceEvent(ChannelTrace::Severity severity, grpc_slice data) {
+    trace_->AddTraceEvent(severity, data);
+  }
+  void AddTraceEventWithReference(ChannelTrace::Severity severity,
+                                  grpc_slice data,
+                                  RefCountedPtr<BaseNode> referenced_channel) {
+    trace_->AddTraceEventWithReference(severity, data, referenced_channel);
+  }
   void RecordCallStarted() { call_counter_.RecordCallStarted(); }
   void RecordCallFailed() { call_counter_.RecordCallFailed(); }
   void RecordCallSucceeded() { call_counter_.RecordCallSucceeded(); }
diff --git a/src/core/ext/filters/client_channel/subchannel.cc b/src/core/ext/filters/client_channel/subchannel.cc
index b74a354e9e..639a5fe9db 100644
--- a/src/core/ext/filters/client_channel/subchannel.cc
+++ b/src/core/ext/filters/client_channel/subchannel.cc
@@ -183,7 +183,7 @@ static void connection_destroy(void* arg, grpc_error* error) {
 static void subchannel_destroy(void* arg, grpc_error* error) {
   grpc_subchannel* c = static_cast<grpc_subchannel*>(arg);
   if (c->channelz_subchannel != nullptr) {
-    c->channelz_subchannel->trace()->AddTraceEvent(
+    c->channelz_subchannel->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Subchannel destroyed"));
     c->channelz_subchannel->MarkSubchannelDestroyed();
@@ -397,7 +397,7 @@ grpc_subchannel* grpc_subchannel_create(grpc_connector* connector,
     c->channelz_subchannel =
         grpc_core::MakeRefCounted<grpc_core::channelz::SubchannelNode>(
             c, channel_tracer_max_nodes);
-    c->channelz_subchannel->trace()->AddTraceEvent(
+    c->channelz_subchannel->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Subchannel created"));
   }
diff --git a/src/core/lib/channel/channelz.h b/src/core/lib/channel/channelz.h
index 6e20f31b68..74b203af44 100644
--- a/src/core/lib/channel/channelz.h
+++ b/src/core/lib/channel/channelz.h
@@ -44,7 +44,8 @@ namespace channelz {
 
 namespace testing {
 class CallCountingHelperPeer;
-}
+class ChannelNodePeer;
+}  // namespace testing
 
 // base class for all channelz entities
 class BaseNode : public RefCounted<BaseNode> {
@@ -131,7 +132,14 @@ class ChannelNode : public BaseNode {
   bool ChannelIsDestroyed() { return channel_ == nullptr; }
 
   // proxy methods to composed classes.
-  ChannelTrace* trace() { return trace_.get(); }
+  void AddTraceEvent(ChannelTrace::Severity severity, grpc_slice data) {
+    trace_->AddTraceEvent(severity, data);
+  }
+  void AddTraceEventWithReference(ChannelTrace::Severity severity,
+                                  grpc_slice data,
+                                  RefCountedPtr<BaseNode> referenced_channel) {
+    trace_->AddTraceEventWithReference(severity, data, referenced_channel);
+  }
   void RecordCallStarted() { call_counter_.RecordCallStarted(); }
   void RecordCallFailed() { call_counter_.RecordCallFailed(); }
   void RecordCallSucceeded() { call_counter_.RecordCallSucceeded(); }
@@ -141,8 +149,12 @@ class ChannelNode : public BaseNode {
   char* target_view() { return target_.get(); }
   // provides access to call_counter_ for child.
   CallCountingHelper* call_counter() { return &call_counter_; }
+  // provides access to channel trace for child.
+  ChannelTrace* trace() { return trace_.get(); }
 
  private:
+  // to allow the channel trace test to access trace();
+  friend class testing::ChannelNodePeer;
   grpc_channel* channel_ = nullptr;
   UniquePtr<char> target_;
   CallCountingHelper call_counter_;
diff --git a/src/core/lib/surface/channel.cc b/src/core/lib/surface/channel.cc
index 01caadaaba..0b3508e27c 100644
--- a/src/core/lib/surface/channel.cc
+++ b/src/core/lib/surface/channel.cc
@@ -170,7 +170,7 @@ grpc_channel* grpc_channel_create_with_builder(
     bool is_top_level_channel = channel->is_client && !internal_channel;
     channel->channelz_channel = channel_node_create_func(
         channel, channel_tracer_max_nodes, is_top_level_channel);
-    channel->channelz_channel->trace()->AddTraceEvent(
+    channel->channelz_channel->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Channel created"));
   }
@@ -417,7 +417,7 @@ void grpc_channel_internal_unref(grpc_channel* c REF_ARG) {
 static void destroy_channel(void* arg, grpc_error* error) {
   grpc_channel* channel = static_cast<grpc_channel*>(arg);
   if (channel->channelz_channel != nullptr) {
-    channel->channelz_channel->trace()->AddTraceEvent(
+    channel->channelz_channel->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Channel destroyed"));
     channel->channelz_channel->MarkChannelDestroyed();