[vm] Finish removing legacy restart mechanism.

Cf. a4adbff.

TEST=ci
Change-Id: I9d2517c6cb0b5630990d087812e9a54241f41bb8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/280043
Reviewed-by: Alexander Aprelev <[email protected]>
Commit-Queue: Ryan Macnak <[email protected]>

Author: rmacnak-google

runtime/vm/message_handler.cc

@@ -44,8 +44,6 @@ const char* MessageHandler::MessageStatusString(MessageStatus status) {
       return "OK";
     case kError:
       return "Error";
-    case kRestart:
-      return "Restart";
     case kShutdown:
       return "Shutdown";
     default:
@@ -358,19 +356,17 @@ bool MessageHandler::ShouldPauseOnStart(MessageStatus status) const {
   }
   // If we are restarting or shutting down, we do not want to honor
   // should_pause_on_start or should_pause_on_exit.
-  return (status != MessageHandler::kRestart &&
-          status != MessageHandler::kShutdown) &&
-         should_pause_on_start() && owning_isolate->is_runnable();
+  return (status != MessageHandler::kShutdown) && should_pause_on_start() &&
+         owning_isolate->is_runnable();
 }
 
 bool MessageHandler::ShouldPauseOnExit(MessageStatus status) const {
   Isolate* owning_isolate = isolate();
   if (owning_isolate == NULL) {
     return false;
   }
-  return (status != MessageHandler::kRestart &&
-          status != MessageHandler::kShutdown) &&
-         should_pause_on_exit() && owning_isolate->is_runnable();
+  return (status != MessageHandler::kShutdown) && should_pause_on_exit() &&
+         owning_isolate->is_runnable();
 }
 #endif
 

runtime/vm/message_handler.h

@@ -25,7 +25,6 @@ class MessageHandler {
   enum MessageStatus {
     kOK,        // We successfully handled a message.
     kError,     // We encountered an error handling a message.
-    kRestart,   // The VM is restarting.
     kShutdown,  // The VM is shutting down.
   };
   static const char* MessageStatusString(MessageStatus status);