Sane asynchronous debugging and stack traces

runtime/vm/scopes.cc

Index: runtime/vm/scopes.cc
diff --git a/runtime/vm/scopes.cc b/runtime/vm/scopes.cc
index 75f5d688bf59de6de2765c8cbac70974820850f5..d75d4ca943c832a93996d40542b8974532350788 100644
--- a/runtime/vm/scopes.cc
+++ b/runtime/vm/scopes.cc
@@ -261,7 +261,19 @@ int LocalScope::AllocateVariables(int first_parameter_index,
 static bool IsFilteredIdentifier(const String& str) {
   ASSERT(str.Length() > 0);
   if (str.raw() == Symbols::AsyncOperation().raw()) {
-    // Keep :async_op for asynchronous debugging.
+    // Keep :async_op for await debugging.
+    return false;
+  }
+  if (str.raw() == Symbols::AsyncCompleter().raw()) {
+    // Keep :async_completer for await debugging.
+    return false;
+  }
+  if (str.raw() == Symbols::ControllerStream().raw()) {
+    // Keep :controller_sstream for await debugging.
+    return false;
+  }
+  if (str.raw() == Symbols::AwaitJumpVar().raw()) {
+    // Keep :await_jump_for for await debugging.
     return false;
   }
   return str.CharAt(0) == ':';