bluetooth: Use WebBluetoothDeviceId instead of string

components/web_bluetooth/web_bluetooth_device_id.h

Index: components/web_bluetooth/web_bluetooth_device_id.h
diff --git a/components/web_bluetooth/web_bluetooth_device_id.h b/components/web_bluetooth/web_bluetooth_device_id.h
new file mode 100644
index 0000000000000000000000000000000000000000..cd96e6d5a65f2292592824f0c4d62df2beb3b07a
--- /dev/null
+++ b/components/web_bluetooth/web_bluetooth_device_id.h
@@ -0,0 +1,55 @@
+// 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 COMPONENTS_WEB_BLUETOOTH_WEB_BLUETOOTH_DEVICE_ID_H_
+#define COMPONENTS_WEB_BLUETOOTH_WEB_BLUETOOTH_DEVICE_ID_H_
+
+#include <string>
+
+namespace web_bluetooth {
+
+// Used to uniquely identify a Bluetooth Device for an Origin.
+// A WebBluetoothDeviceId is generated by base64-encoding a 128bit
+// string.
+class WebBluetoothDeviceId {
+ public:
+  // Default constructor that creates an invalid id. We implement it so that
+  // instances 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.
+  WebBluetoothDeviceId();
+
+  // DCHECKS that |device_id| is valid.
+  explicit WebBluetoothDeviceId(std::string device_id);
+  ~WebBluetoothDeviceId();
+
+  // Returns the string that represents this WebBluetoothDeviceId.
+  const std::string& str() const;
+
+  // The returned WebBluetoothDeviceId is generated by creating a random 128bit
+  // string and base64-encoding it.
+  static WebBluetoothDeviceId Create();
+
+  // Returns true if base64-decoding |device_id| results in a 128bit string.
+  static bool IsValid(const std::string& device_id);
+
+  bool operator==(const WebBluetoothDeviceId& device_id) const;
+  bool operator!=(const WebBluetoothDeviceId& device_id) const;
+
+ private:
+  std::string device_id_;
+};
+
+std::ostream& operator<<(std::ostream& out,
+                         const WebBluetoothDeviceId& device_id);
+
+struct WebBluetoothDeviceIdHash {
+  size_t operator()(const WebBluetoothDeviceId& device_id) const {
+    return std::hash<std::string>()(device_id.str());
+  }
+};
+
+}  // namespace web_bluetooth
+
+#endif  // COMPONENTS_WEB_BLUETOOTH_WEB_BLUETOOTH_DEVICE_ID_H_