reviewer feedback

src/core/ext/filters/client_channel/client_channel_channelz.cc

@@ -155,12 +155,11 @@ SubchannelNode::SubchannelNode(grpc_subchannel* subchannel,
                                size_t channel_tracer_max_nodes)
     : BaseNode(EntityType::kSubchannel),
       subchannel_(subchannel),
-      target_(UniquePtr<char>(
+      target_(
-          gpr_strdup(grpc_subchannel_get_target(subchannel_)))) {
+          UniquePtr<char>(gpr_strdup(grpc_subchannel_get_target(subchannel_)))),
-  trace_.Init(channel_tracer_max_nodes);
+      trace_(channel_tracer_max_nodes) {}
-}
 
-SubchannelNode::~SubchannelNode() { trace_.Destroy(); }
+SubchannelNode::~SubchannelNode() {}
 
 void SubchannelNode::PopulateConnectivityState(grpc_json* json) {
   grpc_connectivity_state state;
@@ -199,7 +198,7 @@ grpc_json* SubchannelNode::RenderJson() {
   grpc_json_create_child(nullptr, json, "target", target_.get(),
                          GRPC_JSON_STRING, false);
   // fill in the channel trace if applicable
-  grpc_json* trace_json = trace_->RenderJson();
+  grpc_json* trace_json = trace_.RenderJson();
   if (trace_json != nullptr) {
     trace_json->key = "trace";  // this object is named trace in channelz.proto
     grpc_json_link_child(json, trace_json, nullptr);

src/core/ext/filters/client_channel/client_channel_channelz.h

@@ -23,6 +23,7 @@
 
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/channel_stack.h"
+#include "src/core/lib/channel/channel_trace.h"
 #include "src/core/lib/channel/channelz.h"
 #include "src/core/lib/gprpp/inlined_vector.h"
 
@@ -78,12 +79,12 @@ class SubchannelNode : public BaseNode {
 
   // proxy methods to composed classes.
   void AddTraceEvent(ChannelTrace::Severity severity, grpc_slice data) {
-    trace_->AddTraceEvent(severity, data);
+    trace_.AddTraceEvent(severity, data);
   }
   void AddTraceEventWithReference(ChannelTrace::Severity severity,
                                   grpc_slice data,
                                   RefCountedPtr<BaseNode> referenced_channel) {
-    trace_->AddTraceEventWithReference(severity, data, referenced_channel);
+    trace_.AddTraceEventWithReference(severity, data, referenced_channel);
   }
   void RecordCallStarted() { call_counter_.RecordCallStarted(); }
   void RecordCallFailed() { call_counter_.RecordCallFailed(); }
@@ -93,7 +94,7 @@ class SubchannelNode : public BaseNode {
   grpc_subchannel* subchannel_;
   UniquePtr<char> target_;
   CallCountingHelper call_counter_;
-  ManualConstructor<ChannelTrace> trace_;
+  ChannelTrace trace_;
 
   void PopulateConnectivityState(grpc_json* json);
 };

src/core/lib/channel/channelz.cc

@@ -92,11 +92,10 @@ ChannelNode::ChannelNode(grpc_channel* channel, size_t channel_tracer_max_nodes,
     : BaseNode(is_top_level_channel ? EntityType::kTopLevelChannel
                                     : EntityType::kInternalChannel),
       channel_(channel),
-      target_(UniquePtr<char>(grpc_channel_get_target(channel_))) {
+      target_(UniquePtr<char>(grpc_channel_get_target(channel_))),
-  trace_.Init(channel_tracer_max_nodes);
+      trace_(channel_tracer_max_nodes) {}
-}
 
-ChannelNode::~ChannelNode() { trace_.Destroy(); }
+ChannelNode::~ChannelNode() {}
 
 grpc_json* ChannelNode::RenderJson() {
   // We need to track these three json objects to build our object
@@ -123,7 +122,7 @@ grpc_json* ChannelNode::RenderJson() {
   grpc_json_create_child(nullptr, json, "target", target_.get(),
                          GRPC_JSON_STRING, false);
   // fill in the channel trace if applicable
-  grpc_json* trace_json = trace_->RenderJson();
+  grpc_json* trace_json = trace_.RenderJson();
   if (trace_json != nullptr) {
     trace_json->key = "trace";  // this object is named trace in channelz.proto
     grpc_json_link_child(json, trace_json, nullptr);

src/core/lib/channel/channelz.h

@@ -133,12 +133,12 @@ class ChannelNode : public BaseNode {
 
   // proxy methods to composed classes.
   void AddTraceEvent(ChannelTrace::Severity severity, grpc_slice data) {
-    trace_->AddTraceEvent(severity, data);
+    trace_.AddTraceEvent(severity, data);
   }
   void AddTraceEventWithReference(ChannelTrace::Severity severity,
                                   grpc_slice data,
                                   RefCountedPtr<BaseNode> referenced_channel) {
-    trace_->AddTraceEventWithReference(severity, data, referenced_channel);
+    trace_.AddTraceEventWithReference(severity, data, referenced_channel);
   }
   void RecordCallStarted() { call_counter_.RecordCallStarted(); }
   void RecordCallFailed() { call_counter_.RecordCallFailed(); }
@@ -150,7 +150,7 @@ class ChannelNode : public BaseNode {
   // 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(); }
+  ChannelTrace* trace() { return &trace_; }
 
  private:
   // to allow the channel trace test to access trace();
@@ -158,7 +158,7 @@ class ChannelNode : public BaseNode {
   grpc_channel* channel_ = nullptr;
   UniquePtr<char> target_;
   CallCountingHelper call_counter_;
-  ManualConstructor<ChannelTrace> trace_;
+  ChannelTrace trace_;
 };
 
 // Handles channelz bookkeeping for servers