Track async causal stack traces

runtime/vm/vm_sources.gypi

 # 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.
 
 # This file contains all sources (vm and tests) for the dart virtual machine.
 # Unit test files need to have a '_test' suffix appended to the name.
 {
   'sources': [
     'allocation.cc',
     'allocation.h',
@@ skipping 458 matching lines @@
     'source_report_test.cc',
     'spaces.h',
     'stack_frame.cc',
     'stack_frame.h',
     'stack_frame_arm.h',
     'stack_frame_arm64.h',
     'stack_frame_ia32.h',
     'stack_frame_mips.h',
     'stack_frame_test.cc',
     'stack_frame_x64.h',
+    'stack_trace.cc',
+    'stack_trace.h',
     'store_buffer.cc',
     'store_buffer.h',
     'stub_code.cc',
     'stub_code.h',
     'stub_code_arm.cc',
     'stub_code_arm_test.cc',
     'stub_code_arm64.cc',
     'stub_code_arm64_test.cc',
     'stub_code_dbc.cc',
     'stub_code_ia32.cc',
@@ skipping 61 matching lines @@
     'visitor.h',
     'weak_code.cc',
     'weak_code.h',
     'weak_table.cc',
     'weak_table.h',
     'zone.cc',
     'zone.h',
     'zone_test.cc',
   ],
 }