Revert of Revert of [Easy Unlock] Port the BluetoothConnectionFinder class to native code.

components/proximity_auth/connection_finder.h

Index: components/proximity_auth/connection_finder.h
diff --git a/components/proximity_auth/connection_finder.h b/components/proximity_auth/connection_finder.h
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index 0000000000000000000000000000000000000000..51292da55438b3c093082b125bd01e1ef29ac474
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+++ b/components/proximity_auth/connection_finder.h
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+// 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.
+
+#ifndef COMPONENTS_PROXIMITY_AUTH_CONNECTION_FINDER_H
+#define COMPONENTS_PROXIMITY_AUTH_CONNECTION_FINDER_H
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace proximity_auth {
+
+class Connection;
+
+// Interface for finding a connection to a remote device.
+class ConnectionFinder {
+ public:
+  ConnectionFinder() {}
+  virtual ~ConnectionFinder() {}
+
+  // Attempts to find a connection to a remote device. The finder will try to
+  // find the connection indefinitely until the finder is destroyed. Calls
+  // |connection_callback| with the open connection once the remote device is
+  // connected.
+  // TODO(isherman): Can this just be done as part of the constructor?
+  typedef base::Callback<void(scoped_ptr<Connection> connection)>
+      ConnectionCallback;
+  virtual void Find(const ConnectionCallback& connection_callback) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ConnectionFinder);
+};
+
+}  // namespace proximity_auth
+
+#endif  // COMPONENTS_PROXIMITY_AUTH_CONNECTION_FINDER_H