xDS plugin is going to use LRS stream to report load to balancer. Remove

the current grpclb specific load reporting from the implementation.

The changes here also mean that the plugin will just get the initial
response and no subsequent response from the balancer.

src/core/ext/filters/client_channel/lb_policy/xds/xds.cc

@@ -668,16 +668,17 @@ bool XdsLb::BalancerCallState::LoadReportCountersAreZero(
          (drop_entries == nullptr || drop_entries->empty());
 }
 
+// TODO(vpowar): Use LRS to send the client Load Report.
 void XdsLb::BalancerCallState::SendClientLoadReportLocked() {
   // Construct message payload.
   GPR_ASSERT(send_message_payload_ == nullptr);
   xds_grpclb_request* request =
       xds_grpclb_load_report_request_create_locked(client_stats_.get());
+
   // Skip client load report if the counters were all zero in the last
   // report and they are still zero in this one.
   if (LoadReportCountersAreZero(request)) {
     if (last_client_load_report_counters_were_zero_) {
-      xds_grpclb_request_destroy(request);
       ScheduleNextClientLoadReportLocked();
       return;
     }
@@ -685,25 +686,8 @@ void XdsLb::BalancerCallState::SendClientLoadReportLocked() {
   } else {
     last_client_load_report_counters_were_zero_ = false;
   }
-  grpc_slice request_payload_slice = xds_grpclb_request_encode(request);
-  send_message_payload_ =
-      grpc_raw_byte_buffer_create(&request_payload_slice, 1);
-  grpc_slice_unref_internal(request_payload_slice);
+  // TODO(vpowar): Send the report on LRS stream.
   xds_grpclb_request_destroy(request);
-  // Send the report.
-  grpc_op op;
-  memset(&op, 0, sizeof(op));
-  op.op = GRPC_OP_SEND_MESSAGE;
-  op.data.send_message.send_message = send_message_payload_;
-  GRPC_CLOSURE_INIT(&client_load_report_closure_, ClientLoadReportDoneLocked,
-                    this, grpc_combiner_scheduler(xdslb_policy()->combiner()));
-  grpc_call_error call_error = grpc_call_start_batch_and_execute(
-      lb_call_, &op, 1, &client_load_report_closure_);
-  if (GPR_UNLIKELY(call_error != GRPC_CALL_OK)) {
-    gpr_log(GPR_ERROR, "[xdslb %p] call_error=%d", xdslb_policy_.get(),
-            call_error);
-    GPR_ASSERT(GRPC_CALL_OK == call_error);
-  }
 }
 
 void XdsLb::BalancerCallState::ClientLoadReportDoneLocked(void* arg,