Avoid sync IPCs for FileSystem API

chrome/renderer/permission_request_map.cc

+// Copyright 2014 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 "chrome/renderer/permission_request_map.h"
+
+#include "base/lazy_instance.h"
+#include "base/threading/thread_local.h"
+#include "third_party/WebKit/public/platform/WebPermissionCallbacks.h"
+
+using blink::WebPermissionCallbacks;
+
+namespace content {
+
+namespace {
+
+base::LazyInstance<base::ThreadLocalPointer<PermissionRequestMap> >::Leaky
+    g_permission_request_map_tls = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+PermissionRequestMap::PermissionRequestMap() {
+}
+
+// static
+PermissionRequestMap* PermissionRequestMap::Get() {
+  return g_permission_request_map_tls.Pointer()->Get();
+}
+
+// static
+PermissionRequestMap* PermissionRequestMap::GetOrCreate() {
+  if (g_permission_request_map_tls.Pointer()->Get())
+    return g_permission_request_map_tls.Pointer()->Get();
+  PermissionRequestMap* map = new PermissionRequestMap;
+  g_permission_request_map_tls.Pointer()->Set(map);
+  return map;
+}
+
+PermissionRequestMap::~PermissionRequestMap() {
+  IDMap<WebPermissionCallbacks>::iterator iter(&permission_request_map_);
+  while (!iter.IsAtEnd()) {
+    iter.GetCurrentValue()->doDeny();
+    iter.Advance();
+  }
+  g_permission_request_map_tls.Pointer()->Set(NULL);
+}
+
+int PermissionRequestMap::RegisterPermissionCallbacks(
+    const WebPermissionCallbacks& callbacks) {
+  return permission_request_map_.Add(new WebPermissionCallbacks(callbacks));
+}
+
+WebPermissionCallbacks* PermissionRequestMap::GetAndUnregisterCallbacks(
+    int callbacks_id) {
+  WebPermissionCallbacks* callbacks =
+      permission_request_map_.Lookup(callbacks_id);
+  permission_request_map_.Remove(callbacks_id);
+  return callbacks;
+}
+
+}  // namespace content