Fixes crashes in VM isolate shutdown.

runtime/vm/debugger.cc

 // Copyright (c) 2012, 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/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 1197 matching lines @@
     latent_locations_ = latent_locations_->next();
     delete bpt;
   }
   while (code_breakpoints_ != NULL) {
     CodeBreakpoint* bpt = code_breakpoints_;
     code_breakpoints_ = code_breakpoints_->next();
     bpt->Disable();
     delete bpt;
   }
   // Signal isolate shutdown event.
-  if (!ServiceIsolate::IsServiceIsolateDescendant(isolate_)) {
+  if (!ServiceIsolate::IsServiceIsolateDescendant(isolate_) &&
+      (isolate_ != Dart::vm_isolate())) {

[Cutch, 2015/06/09 14:57:33]

I think the real bug is that the vm-isolate shouldn't have a debugger in the
first place.

[zra, 2015/06/09 15:45:17]

Ah, yah. That makes sense. I'll see if I can get rid of it.

[zra, 2015/06/09 17:29:01]

Done. Removed debugger from vm isolate, and added asserts on access to
isolate->debugger().

     SignalIsolateEvent(DebuggerEvent::kIsolateShutdown);
   }
 }
 
 
 static RawFunction* ResolveLibraryFunction(
                         const Library& library,
                         const String& fname) {
   ASSERT(!library.IsNull());
   const Object& object = Object::Handle(library.ResolveName(fname));
@@ skipping 1723 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart