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

components/proximity_auth/throttled_bluetooth_connection_finder.cc

+// 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.
+
+#include "components/proximity_auth/throttled_bluetooth_connection_finder.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/task_runner.h"
+#include "base/time/time.h"
+#include "components/proximity_auth/bluetooth_connection_finder.h"
+#include "components/proximity_auth/bluetooth_throttler.h"
+#include "components/proximity_auth/connection.h"
+
+namespace proximity_auth {
+
+ThrottledBluetoothConnectionFinder::ThrottledBluetoothConnectionFinder(
+    scoped_ptr<BluetoothConnectionFinder> connection_finder,
+    scoped_refptr<base::TaskRunner> task_runner,
+    BluetoothThrottler* throttler)
+    : connection_finder_(connection_finder.Pass()),
+      task_runner_(task_runner),
+      throttler_(throttler),
+      connection_(nullptr),
+      weak_ptr_factory_(this) {
+}
+
+ThrottledBluetoothConnectionFinder::~ThrottledBluetoothConnectionFinder() {
+  if (connection_)
+    connection_->RemoveObserver(this);
+}
+
+void ThrottledBluetoothConnectionFinder::Find(
+    const ConnectionCallback& connection_callback) {
+  const base::TimeDelta delay = throttler_->GetDelay();
+
+  // Wait, if needed.
+  if (delay != base::TimeDelta()) {
+    task_runner_->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&ThrottledBluetoothConnectionFinder::Find,
+                   weak_ptr_factory_.GetWeakPtr(), connection_callback),
+        delay);
+    return;
+  }
+
+  connection_finder_->Find(
+      base::Bind(&ThrottledBluetoothConnectionFinder::OnConnection,
+                 weak_ptr_factory_.GetWeakPtr(), connection_callback));
+}
+
+void ThrottledBluetoothConnectionFinder::OnConnection(
+    const ConnectionCallback& connection_callback,
+    scoped_ptr<Connection> connection) {
+  DCHECK(!connection_);
+  connection_ = connection.get();
+  connection_->AddObserver(this);
+
+  connection_callback.Run(connection.Pass());
+}
+
+void ThrottledBluetoothConnectionFinder::OnConnectionStatusChanged(
+    const Connection& connection,
+    Connection::Status old_status,
+    Connection::Status new_status) {
+  DCHECK_EQ(&connection, connection_);
+  if (old_status == Connection::CONNECTED &&
+      new_status == Connection::DISCONNECTED) {
+    throttler_->OnConnectionClosed();

[Tim Song, 2015/04/17 22:34:31]

Using the ThrottledBluetoothConnectionFinder instance as an observer may be
problematic if the controller does not keep the ConnectionFinder around after it
finds a connection. Wouldn't it be better for the throttler to be the observer?

[Ilya Sherman, 2015/04/22 00:48:59]

Good point.  Done.

+    connection_->RemoveObserver(this);
+    connection_ = nullptr;
+  }
+}
+
+}  // namespace proximity_auth