Fix product build

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "lib/stacktrace.h"
@@ skipping 5944 matching lines @@
   bool success = StreamTraceEvents(consumer, user_data, &js, false);
   FinishStreamToConsumer(consumer, user_data, "timeline");
   return success;
 }
 
 
 DART_EXPORT void Dart_SetEmbedderTimelineCallbacks(
     Dart_EmbedderTimelineStartRecording start_recording,
     Dart_EmbedderTimelineStopRecording stop_recording,
     Dart_EmbedderTimelineGetTimeline get_timeline) {
+  if (!FLAG_support_timeline) {
+    return;
+  }
   Timeline::set_start_recording_cb(start_recording);
   Timeline::set_stop_recording_cb(stop_recording);
   Timeline::set_get_timeline_cb(get_timeline);
 }
 
 
 DART_EXPORT bool Dart_GlobalTimelineGetTrace(Dart_StreamConsumer consumer,
                                              void* user_data) {
   if (!FLAG_support_timeline) {
     return false;
@@ skipping 248 matching lines @@
   return Api::Success();
 }
 #endif  // DART_PRECOMPILER
 
 
 DART_EXPORT bool Dart_IsRunningPrecompiledCode() {
   return Dart::IsRunningPrecompiledCode();
 }
 
 }  // namespace dart