VM restart + shutdown fixes

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index 422e4d0ab1dc715863b3fa665a2b31d2247678b9..3d14a2fd86d23a0b3c598b14a7cf8f7c21b25a30 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -129,6 +129,7 @@ class Isolate : public BaseIsolate {
     // Internal message ids.
     kInterruptMsg = 10,     // Break in the debugger.
     kInternalKillMsg = 11,  // Like kill, but does not run exit listeners, etc.
+    kVMRestartMsg = 12,     // Sent to isolates when vm is restarting.
   };
   // The different Isolate API message priorities for ping and kill messages.
   enum LibMsgPriority {
@@ -766,6 +767,9 @@ class Isolate : public BaseIsolate {
 
   bool is_service_isolate() const { return is_service_isolate_; }
 
+  // The isolates_list_monitor_ should be held when calling Kill().
+  void KillLocked(LibMsgId msg_id = kInternalKillMsg);

[zra, 2015/10/05 16:56:47]

Maybe instead of making this public, make RestartVMIsolateVisitor a friend?
Otherwise if this should stay public, then IsolateKillerVisitor no longer needs
to be a friend. Also, I'd prefer just explicitly passing the LibMsgId
everywhere. There shouldn't be many call sites to fix.

[Cutch, 2015/10/05 18:10:46]

+1 to suggestion of dropping default msg_id value.

[turnidge, 2015/10/05 22:18:24]

I have made this private again.  I have added a msg_id parameter to
KillAllIsolates/KillIfExists and gotten rid of RestartVMIsolateVisitor.

+
   static void KillAllIsolates();
   static void KillIfExists(Isolate* isolate);
 
@@ -783,9 +787,6 @@ class Isolate : public BaseIsolate {
                        const Dart_IsolateFlags& api_flags,
                        bool is_vm_isolate = false);
 
-  // The isolates_list_monitor_ should be held when calling Kill().
-  void KillLocked();
-
   void LowLevelShutdown();
   void Shutdown();
   void ReclaimTimelineBlocks();