Fixes shutdown crashes.

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 1259 matching lines @@
   ASSERT(!IsPaused());
   ASSERT(latent_locations_ == NULL);
   ASSERT(breakpoint_locations_ == NULL);
   ASSERT(code_breakpoints_ == NULL);
   ASSERT(stack_trace_ == NULL);
   ASSERT(obj_cache_ == NULL);
 }
 
 
 void Debugger::Shutdown() {
+  // TODO(johnmccutchan): Do not create a debugger for isolates that don't need
+  // them. Then, assert here that isolate_ is not one of those isolates.
+  if ((isolate_ == Dart::vm_isolate()) ||
+      ServiceIsolate::IsServiceIsolateDescendant(isolate_)) {
+    return;
+  }
   while (breakpoint_locations_ != NULL) {
     BreakpointLocation* bpt = breakpoint_locations_;
     breakpoint_locations_ = breakpoint_locations_->next();
     delete bpt;
   }
   while (latent_locations_ != NULL) {
     BreakpointLocation* bpt = latent_locations_;
     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_)) {
-    SignalIsolateEvent(DebuggerEvent::kIsolateShutdown);
-  }
+  SignalIsolateEvent(DebuggerEvent::kIsolateShutdown);
 }
 
 
 static RawFunction* ResolveLibraryFunction(
                         const Library& library,
                         const String& fname) {
   ASSERT(!library.IsNull());
   const Object& object = Object::Handle(library.ResolveName(fname));
   if (!object.IsNull() && object.IsFunction()) {
     return Function::Cast(object).raw();
@@ skipping 1930 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart