Remove deprecated call Dart_Error from the API. There are no uses of it.

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 367 matching lines @@
     const UnhandledException& error = UnhandledException::Cast(obj);
     return Api::NewHandle(isolate, error.stacktrace());
   } else if (obj.IsError()) {
     return Api::NewError("This error is not an unhandled exception error.");
   } else {
     return Api::NewError("Can only get stacktraces from error handles.");
   }
 }
 
 
-// Deprecated.
-// TODO(turnidge): Remove all uses and delete.
-DART_EXPORT Dart_Handle Dart_Error(const char* error) {
-  return Dart_NewApiError(error);
-}
-
-
 // TODO(turnidge): This clones Api::NewError.  I need to use va_copy to
 // fix this but not sure if it available on all of our builds.
 DART_EXPORT Dart_Handle Dart_NewApiError(const char* error) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   CHECK_CALLBACK_STATE(isolate);
 
   const String& message = String::Handle(isolate, String::New(error));
   return Api::NewHandle(isolate, ApiError::New(message));
 }
@@ skipping 4004 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success();
 }
 
 }  // namespace dart