Fix issue 3636, break on exception

runtime/vm/exceptions.cc

 // Copyright (c) 2011, 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/exceptions.h"
 
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/flags.h"
@@ skipping 228 matching lines @@
     }
   }
   // Throw TypeError instance.
   Exceptions::Throw(type_error);
   UNREACHABLE();
 }
 
 
 void Exceptions::Throw(const Instance& exception) {
   Isolate* isolate = Isolate::Current();
-  if (isolate->debugger()->IsActive()) {
-    isolate->debugger()->SignalExceptionThrown(exception);
-  }
+  isolate->debugger()->SignalExceptionThrown(exception);
   // Null object is a valid exception object.
   ThrowExceptionHelper(exception, Instance::Handle(isolate));
 }
 
 
 void Exceptions::ReThrow(const Instance& exception,
                          const Instance& stacktrace) {
   // Null object is a valid exception object.
   ThrowExceptionHelper(exception, stacktrace);
 }
@@ skipping 99 matching lines @@
     case kIsolateSpawn:
       library = Library::IsolateLibrary();
       class_name = String::NewSymbol("IsolateSpawnException");
       break;
   }
 
   return DartLibraryCalls::ExceptionCreate(library, class_name, arguments);
 }
 
 }  // namespace dart