bluetooth: Use WebBluetoothDeviceId instead of string

content/common/bluetooth/bluetooth_device_id.h

+// Copyright 2016 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 CONTENT_COMMON_BLUETOOTH_BLUETOOTH_DEVICE_ID_H_
+#define CONTENT_COMMON_BLUETOOTH_BLUETOOTH_DEVICE_ID_H_
+
+#include <string>
+
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Used to uniquely identify a Bluetooth Device for an Origin.
+// A BluetoothDeviceId is generated by base64-encoding a 128bit
+// string.
+class CONTENT_EXPORT BluetoothDeviceId {

[Jeffrey Yasskin, 2016/06/03 17:22:05]

I wish I could think of a way to make it clear that this is the origin-specific
ID, and not, say, the ID that BluetoothDevice::GetIdentifier() returns. But I
don't have a good alternative name (BluetoothDeviceIdForOrigin is too long), so
this is fine.

[ortuno, 2016/06/06 22:22:59]

Ack.

+ public:
+  // Default constructor that does nothing. We implement it so that instances

[Jeffrey Yasskin, 2016/06/03 17:22:05]

s/does nothing/creates an invalid Id/

[ortuno, 2016/06/06 22:22:59]

Done.

+  // of this class in a container, e.g. std::unordered_map, can be accessed
+  // through the [] operator. Trying to call any function of the resulting
+  // object will DCHECK-fail.
+  BluetoothDeviceId();
+
+  // DCHEKS that |device_id| is valid.
+  explicit BluetoothDeviceId(const std::string& device_id);
+  ~BluetoothDeviceId();
+
+  // Returns the string that represents this BluetoothDeviceId.
+  const std::string& str() const;
+
+  // The returned BluetoothDeviceId is generated by creating a random 128bit
+  // string and base64-enconding it.

[Jeffrey Yasskin, 2016/06/03 17:22:05]

sp: enconding

[ortuno, 2016/06/06 22:22:59]

Done.

+  static BluetoothDeviceId Create();
+
+  // Returns true if base64-decoding |device_id| results in a 128bit string.
+  static bool IsValid(const std::string& device_id);
+
+  bool operator==(const BluetoothDeviceId& device_id) const;
+  bool operator!=(const BluetoothDeviceId& device_id) const;
+
+ private:
+  std::string device_id_;
+};
+
+// This is required by gtest to print a readable output on test failures.
+void CONTENT_EXPORT PrintTo(const BluetoothDeviceId& device_id,

[Jeffrey Yasskin, 2016/06/03 17:22:05]

I'd prefer to just define operator<< so that we can stream these to LOGs easily.
It's also not banned anymore:
https://google.github.io/styleguide/cppguide.html#Streams.

[ortuno, 2016/06/06 22:22:59]

Done.

+                            std::ostream* out);
+
+}  // namespace content
+
+namespace std {
+
+template <>
+struct hash<content::BluetoothDeviceId> {
+  size_t operator()(const content::BluetoothDeviceId& device_id) const {
+    return std::hash<std::string>()(device_id.str());
+  }
+};
+
+}  // namespace std
+
+#endif  // CONTENT_COMMON_BLUETOOTH_BLUETOOTH_DEVICE_ID_H_