[Extensions Bindings] Add lastError utilities to APIBindingJSUtil

extensions/renderer/api_last_error.cc

 // Copyright 2017 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 "extensions/renderer/api_last_error.h"
 
 #include "gin/converter.h"
 #include "gin/handle.h"
 #include "gin/object_template_builder.h"
 #include "gin/wrappable.h"
@@ skipping 128 matching lines @@
 
   // See comment in SetError().
   v8::TryCatch try_catch(isolate);
   try_catch.SetVerbose(true);
 
   // This Delete() can fail, but there's nothing to do if it does (the exception
   // will be caught by the TryCatch above).
   parent->Delete(context, key);
 }
 
+bool APILastError::HasError(v8::Local<v8::Context> context) {
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+
+  // See comment in SetError().
+  v8::TryCatch try_catch(isolate);
+  try_catch.SetVerbose(true);
+
+  v8::Local<v8::Object> parent = get_parent_.Run(context);
+  if (parent.IsEmpty())
+    return false;
+  v8::Local<v8::Value> error;
+  if (!parent->Get(context, gin::StringToSymbol(isolate, kLastErrorProperty))
+           .ToLocal(&error)) {
+    return false;
+  }
+
+  LastErrorObject* last_error = nullptr;
+  return gin::Converter<LastErrorObject*>::FromV8(context->GetIsolate(), error,
+                                                  &last_error);
+}
+
 }  // namespace extensions