bluetooth: Add characteristic list to DeviceDetailsPage in internals page.

device/bluetooth/device.h

Index: device/bluetooth/device.h
diff --git a/device/bluetooth/device.h b/device/bluetooth/device.h
index af7d14e8a26f13a774c27504c4b5fa0b52c5d726..eeda11f21f7da4084c3424bdfbfc73e742db4947 100644
--- a/device/bluetooth/device.h
+++ b/device/bluetooth/device.h
@@ -14,6 +14,7 @@
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "device/bluetooth/bluetooth_gatt_connection.h"
+#include "device/bluetooth/bluetooth_remote_gatt_characteristic.h"
 #include "device/bluetooth/bluetooth_remote_gatt_service.h"
 #include "device/bluetooth/public/interfaces/device.mojom.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
@@ -50,6 +51,8 @@ class Device : public mojom::Device, public device::BluetoothAdapter::Observer {
   void Disconnect() override;
   void GetInfo(const GetInfoCallback& callback) override;
   void GetServices(const GetServicesCallback& callback) override;
+  void GetCharacteristics(const std::string& service_id,
+                          const GetCharacteristicsCallback& callback) override;
 
  private:
   Device(scoped_refptr<device::BluetoothAdapter> adapter,
@@ -60,6 +63,9 @@ class Device : public mojom::Device, public device::BluetoothAdapter::Observer {
   mojom::ServiceInfoPtr ConstructServiceInfoStruct(
       const device::BluetoothRemoteGattService& service);
 
+  void GetCharacteristicsImpl(const std::string& service_id,
+                              const GetCharacteristicsCallback& callback);
+
   const std::string& GetAddress();
 
   // The current BluetoothAdapter.