bluetooth: Add BluetoothGATTCharacteristic IDL and Blink interface

public/platform/modules/bluetooth/WebBluetoothGATTCharacteristic.h

Index: public/platform/modules/bluetooth/WebBluetoothGATTCharacteristic.h
diff --git a/public/platform/modules/bluetooth/WebBluetoothGATTCharacteristic.h b/public/platform/modules/bluetooth/WebBluetoothGATTCharacteristic.h
new file mode 100644
index 0000000000000000000000000000000000000000..3cc66fc29ee6105237c428df611efe9e94563a84
--- /dev/null
+++ b/public/platform/modules/bluetooth/WebBluetoothGATTCharacteristic.h
@@ -0,0 +1,35 @@
+// 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 WebBluetoothGATTCharacteristic_h
+#define WebBluetoothGATTCharacteristic_h
+
+#include "public/platform/WebString.h"
+#include "public/web/WebArrayBuffer.h"
+
+namespace blink {
+
+struct WebBluetoothGATTCharacteristic {
+    WebBluetoothGATTCharacteristic(const WebString& characteristicInstanceID,
+        const WebString& serviceInstanceID,
+        const WebString& uuid)
+        : characteristicInstanceID(characteristicInstanceID)
+        , serviceInstanceID(serviceInstanceID)
+        , uuid(uuid)
+    {
+    }
+
+    // Members corresponding to BluetoothGATTCharacteristic attributes as

[scheib, 2015/06/03 02:52:18]

Let's change the pattern to having this be a class comment instead. 
// Contains members corresponding to ...

[ortuno, 2015/06/03 19:30:45]

Done.

+    // specified in the IDL.
+    const WebString characteristicInstanceID;
+    const WebString serviceInstanceID;
+    const WebString uuid;
+    // TODO(ortuno): Add 'properties' once CharacteristicProperties is implemented.
+    // const WebCharacteristicProperties properties;
+    const WebArrayBuffer value;
+};
+
+} // namespace blink
+
+#endif // WebBluetoothGATTCharacteristic_h