Fix some service protocol isolate lifecycle races

runtime/vm/isolate.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 "vm/isolate.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "platform/text_buffer.h"
@@ skipping 1932 matching lines @@
     JSONObject jsheap(&jsobj, "_heaps");
     heap()->PrintToJSONObject(Heap::kNew, &jsheap);
     heap()->PrintToJSONObject(Heap::kOld, &jsheap);
   }
 
   jsobj.AddProperty("runnable", is_runnable());
   jsobj.AddProperty("livePorts", message_handler()->live_ports());
   jsobj.AddProperty("pauseOnExit", message_handler()->should_pause_on_exit());
 
   if (debugger() != NULL) {
-    if (message_handler()->is_paused_on_start()) {
+    if (!is_runnable()) {
+      // Isolate is not yet runnable.
+      ASSERT(debugger()->PauseEvent() == NULL);
+      ServiceEvent pause_event(this, ServiceEvent::kNone);
+      jsobj.AddProperty("pauseEvent", &pause_event);
+    } else if (message_handler()->is_paused_on_start() ||
+               message_handler()->should_pause_on_start()) {
       ASSERT(debugger()->PauseEvent() == NULL);
       ServiceEvent pause_event(this, ServiceEvent::kPauseStart);
       jsobj.AddProperty("pauseEvent", &pause_event);
     } else if (message_handler()->is_paused_on_exit()) {
       ASSERT(debugger()->PauseEvent() == NULL);
       ServiceEvent pause_event(this, ServiceEvent::kPauseExit);
       jsobj.AddProperty("pauseEvent", &pause_event);
     } else if (debugger()->PauseEvent() != NULL && !resume_request_) {
       ServiceEvent pause_event(debugger()->PauseEvent());
       jsobj.AddProperty("pauseEvent", &pause_event);
@@ skipping 868 matching lines @@
 void IsolateSpawnState::DecrementSpawnCount() {
   ASSERT(spawn_count_monitor_ != NULL);
   ASSERT(spawn_count_ != NULL);
   MonitorLocker ml(spawn_count_monitor_);
   ASSERT(*spawn_count_ > 0);
   *spawn_count_ = *spawn_count_ - 1;
   ml.Notify();
 }
 
 }  // namespace dart