Delete blimp/helium and remove references to it from dependent targets

blimp/helium/result.cc

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "blimp/helium/result.h"
-
-#include "base/logging.h"
-
-namespace blimp {
-namespace helium {
-
-const char* ResultToString(Result result) {
-  switch (result) {
-    case Result::SUCCESS:
-      return "SUCCESS";
-      break;
-#define HELIUM_ERROR(label, value) \
-  case Result::ERR_##label:        \
-    return "ERR_" #label;
-      break;
-#include "blimp/helium/errors.h"
-#undef HELIUM_ERROR
-  }
-
-  NOTREACHED();
-  return "";
-}
-
-}  // namespace helium
-}  // namespace blimp