fixes for asan leak, and proxy test

freeing up payload_bytes.
returning GET response only once.

src/core/lib/channel/http_client_filter.c

@@ -153,7 +153,7 @@ static void hc_mutate_op(grpc_call_element *elem,
 
   /* Decide which HTTP VERB to use */
   grpc_mdelem *method = GRPC_MDELEM_METHOD_POST;
-  if ((op->send_initial_metadata_flags &
+  if (op->send_initial_metadata != NULL && (op->send_initial_metadata_flags &
        GRPC_INITIAL_METADATA_CACHEABLE_REQUEST) &&
       op->send_message != NULL &&
       op->send_message->length < channeld->max_payload_size_for_get) {
@@ -189,6 +189,8 @@ static void hc_mutate_op(grpc_call_element *elem,
         break;
       }
     }
+    calld->on_complete = op->on_complete;
+    op->on_complete = &calld->hc_on_complete;
     op->send_message = NULL;
   }
 
@@ -216,11 +218,6 @@ static void hc_mutate_op(grpc_call_element *elem,
     calld->on_done_recv = op->recv_initial_metadata_ready;
     op->recv_initial_metadata_ready = &calld->hc_on_recv;
   }
-
-  if (op->on_complete != NULL && op->send_message != NULL) {
-    calld->on_complete = op->on_complete;
-    op->on_complete = &calld->hc_on_complete;
-  }
 }
 
 static void hc_start_transport_op(grpc_exec_ctx *exec_ctx,

src/core/lib/channel/http_server_filter.c

@@ -53,6 +53,9 @@ typedef struct call_data {
   grpc_linked_mdelem status;
   grpc_linked_mdelem content_type;
 
+  /* flag to ensure payload_bin is delivered only once */
+  uint8_t payload_bin_delivered;
+
   grpc_metadata_batch *recv_initial_metadata;
   bool *recv_idempotent_request;
   bool *recv_cacheable_request;
@@ -221,10 +224,13 @@ static void hs_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
   call_data *calld = elem->call_data;
   /* Call recv_message_ready if we got the payload via the header field */
   if (calld->seen_payload_bin && calld->recv_message_ready != NULL) {
-    *calld->pp_recv_message = (grpc_byte_stream *)&calld->read_stream;
+    *calld->pp_recv_message = calld->payload_bin_delivered
+                                  ? NULL
+                                  : (grpc_byte_stream *)&calld->read_stream;
     calld->recv_message_ready->cb(exec_ctx, calld->recv_message_ready->cb_arg,
                                   err);
     calld->recv_message_ready = NULL;
+    calld->payload_bin_delivered = true;
   }
   calld->on_complete->cb(exec_ctx, calld->on_complete->cb_arg, err);
 }