Revert "Remove deprecated dart:profiler library"

runtime/lib/profiler_sources.gypi

Index: runtime/lib/profiler_sources.gypi
diff --git a/runtime/lib/developer_sources.gypi b/runtime/lib/profiler_sources.gypi
similarity index 58%
copy from runtime/lib/developer_sources.gypi
copy to runtime/lib/profiler_sources.gypi
index e3f1ea658789977f908c65204ae033f2701a5032..9175427107a3e4c8ffcb9d65e9a7d2c5ebb33ba4 100644
--- a/runtime/lib/developer_sources.gypi
+++ b/runtime/lib/profiler_sources.gypi
@@ -2,16 +2,11 @@
 # 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.
 
-# Sources visible via dart:developer library.
+# Sources list to keep vm/BUILD.gn generate_core_libraries happy.
 
 {
   'sources': [
-    'developer.cc',
-    'developer.dart',
-    'profiler.cc',
-    'profiler.dart',
-    'timeline.cc',
-    'timeline.dart',
+    'empty_source.dart'
   ],
 }