Add an API function to get a debugger stack trace from an error handle.

runtime/vm/dart_api_impl.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 "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
@@ skipping 4232 matching lines @@
     RETURN_TYPE_ERROR(isolate, source, String);
   }
   CHECK_CALLBACK_STATE(isolate);
 
   NoHeapGrowthControlScope no_growth_control;
 
   Library& library = Library::Handle(isolate, Library::LookupLibrary(url_str));
   if (library.IsNull()) {
     library = Library::New(url_str);
     library.Register();
+    library.set_debuggable(true);
   } else if (!library.LoadNotStarted()) {
     // The source for this library has either been loaded or is in the
     // process of loading.  Return an error.
     return Api::NewError("%s: library '%s' has already been loaded.",
                          CURRENT_FUNC, url_str.ToCString());
   }
   const Script& script = Script::Handle(
       isolate, Script::New(url_str, source_str, RawScript::kLibraryTag));
   Dart_Handle result;
   CompileSource(isolate, library, script, &result);
@@ skipping 165 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success();
 }
 
 }  // namespace dart