[Easy Unlock] Port the BluetoothThrottler class to native code.

components/proximity_auth/bluetooth_throttler.h

+// Copyright 2015 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 COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_THROTTLER_H
+#define COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_THROTTLER_H
+
+namespace base {
+class TimeDelta;
+}
+
+namespace proximity_auth {
+
+class Connection;
+
+// An interface for throttling repeated connection attempts to the same device.
+// This throttling is necessary to prevent a kernel race condition when
+// connecting before the previous connection fully closes, putting the
+// connection in a corrupted, and unrecoverable state. http://crbug.com/345232
+class BluetoothThrottler {
+ public:
+  virtual ~BluetoothThrottler() {}
+
+  // Returns the current delay that must be respected prior to reattempting to
+  // establish a connection with the remote device. The returned value is 0 if
+  // no delay is needed.
+  virtual base::TimeDelta GetDelay() const = 0;
+
+  // Should be called when a connection to the remote device is established.
+  // Note that the |connection| is passed as a weak reference. The throttler
+  // will ensure, by registering as an observer, that it never attempts to use
+  // the connection after it has been destroyed.
+  virtual void OnConnection(Connection* connection) = 0;
+};
+
+}  // namespace proximity_auth
+
+#endif  // COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_THROTTLER_H