Change the ProxyConfigService interface to be asynchronous, and support observers.

The Windows implementation is still using a polling mechanism under the hood, however that polling has been moved to the worker pool so it won't block the IO thread in case WinHttpGetIEProxyConfigForCurrentUser is slow (crbug.com/12189).

BUG=12189

Review URL: http://codereview.chromium.org/3056011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53442 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 49 insertions, 0 deletions

diff --git a/net/proxy/polling_proxy_config_service.h b/net/proxy/polling_proxy_config_service.h
new file mode 100644
index 0000000..1bf889b
--- /dev/null
+++ b/net/proxy/polling_proxy_config_service.h
@@ -0,0 +1,49 @@
+// Copyright (c) 2010 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.
+
+#ifndef NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_
+#define NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_
+
+#include "base/time.h"
+#include "base/ref_counted.h"
+#include "net/proxy/proxy_config_service.h"
+
+namespace net {
+
+// PollingProxyConfigService is a base class for creating ProxyConfigService
+// implementations that use polling to notice when settings have change.
+//
+// It runs code to get the current proxy settings on a background worker
+// thread, and notifies registered observers when the value changes.
+class PollingProxyConfigService : public ProxyConfigService {
+ public:
+  // ProxyConfigService implementation:
+  virtual void AddObserver(Observer* observer);
+  virtual void RemoveObserver(Observer* observer);
+  virtual bool GetLatestProxyConfig(ProxyConfig* config);
+  virtual void OnLazyPoll();
+
+ protected:
+  // Function for retrieving the current proxy configuration.
+  // Implementors must be threadsafe as the function will be invoked from
+  // worker threads.
+  typedef void (*GetConfigFunction)(ProxyConfig*);
+
+  // Creates a polling-based ProxyConfigService which will test for new
+  // settings at most every |poll_interval| time by calling |get_config_func|
+  // on a worker thread.
+  PollingProxyConfigService(
+      base::TimeDelta poll_interval,
+      GetConfigFunction get_config_func);
+
+  virtual ~PollingProxyConfigService();
+
+ private:
+  class Core;
+  scoped_refptr<Core> core_;
+};
+
+}  // namespace net
+
+#endif  // NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_