Track async causal stack traces

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 5094 matching lines @@
         if (!library.IsNull()) {
           return Symbols::True().raw();
         }
       }
     }
     // Check for default VM provided values. If it was not overridden on the
     // command line.
     if (Symbols::DartIsVM().Equals(name)) {
       return Symbols::True().raw();
     }
+    if (FLAG_causal_async_stacks) {
+      if (Symbols::DartDeveloperCausalAsyncStacks().Equals(name)) {
+        return Symbols::True().raw();
+      }
+    }
   }
   return result.raw();
 }
 
 
 RawString* Api::CallEnvironmentCallback(Thread* thread, const String& name) {
   Isolate* isolate = thread->isolate();
   Dart_EnvironmentCallback callback = isolate->environment_callback();
   String& result = String::Handle(thread->zone());
   if (callback != NULL) {
@@ skipping 1694 matching lines @@
 }
 
 
 DART_EXPORT void Dart_DumpNativeStackTrace(void* context) {
 #ifndef PRODUCT
   Profiler::DumpStackTrace(context);
 #endif
 }
 
 }  // namespace dart