Fix an issue with newlines and exception text in the debugger wire protocol.

runtime/bin/dbg_message.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 "bin/dbg_connection.h"
 #include "bin/dbg_message.h"
 #include "bin/dartutils.h"
 #include "bin/thread.h"
 #include "bin/utils.h"
 
@@ skipping 108 matching lines @@
   buf->AddChar('\"');
   for (int i = 0; i < str_len; i++) {
     buf->AddEscapedChar(codepoints[i]);
   }
   buf->AddChar('\"');
   free(codepoints);
 }
 
 
 static void FormatErrorMsg(dart::TextBuffer* buf, Dart_Handle err) {
-  // TODO(hausner): Turn message into Dart string and
-  // properly encode the message.
   ASSERT(Dart_IsError(err));
   const char* msg = Dart_GetError(err);
-  buf->Printf("\"%s\"", msg);
+  Dart_Handle str = Dart_NewStringFromCString(msg);
+  FormatEncodedString(buf, str);
 }
 
 
 static void FormatTextualValue(dart::TextBuffer* buf, Dart_Handle object) {
   Dart_Handle text;
   if (Dart_IsNull(object)) {
     text = Dart_Null();
   } else {
     Dart_ExceptionPauseInfo savedState = Dart_GetExceptionPauseInfo();
 
@@ skipping 948 matching lines @@
     msg_queue->SendIsolateEvent(isolate_id, kind);
     if (kind == kInterrupted) {
       msg_queue->HandleMessages();
     } else {
       ASSERT(kind == kShutdown);
       RemoveIsolateMsgQueue(isolate_id);
     }
   }
   Dart_ExitScope();
 }