bluetooth: Add descriptor list to DeviceDetailsPage on internals page.

device/bluetooth/public/interfaces/device.mojom

Index: device/bluetooth/public/interfaces/device.mojom
diff --git a/device/bluetooth/public/interfaces/device.mojom b/device/bluetooth/public/interfaces/device.mojom
index b8ee6ef753ef3669fd4914f96d7a73351dde2645..fa3065f6ab97d1af22f0210589e761d84cb02f2b 100644
--- a/device/bluetooth/public/interfaces/device.mojom
+++ b/device/bluetooth/public/interfaces/device.mojom
@@ -58,6 +58,11 @@ struct CharacteristicInfo {
   uint32 properties;
 };
 
+struct DescriptorInfo {
+  string id;
+  UUID uuid;
+};
+
 interface Device {
   // Disconnects and deletes the Device.
   Disconnect();
@@ -72,4 +77,12 @@ interface Device {
   // Gets the GATT Characteristics in the GATT Service with |service_id|.
   GetCharacteristics(string service_id) =>
       (array<CharacteristicInfo> characteristics);
+
+  // Gets the GATT Descriptors of the GATT Characteristic with matching
+  // |characteristic_id| in the GATT Service with matching |service_id|.
+  // If |descriptors| is null, an error occured while attempting to retrieve
+  // the array of descriptors. If |descriptors| is empty, this simply
+  // means that no descriptors were found.
+  GetDescriptors(string service_id, string characteristic_id) =>
+      (array<DescriptorInfo>? descriptors);
 };