bluetooth: Add DeviceChanged logging in Device service.

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 b629bab1703d8441c10271394e9345ce2845b566..19fe22e149a9456a58bc29be6bc15738f58b704e 100644
--- a/device/bluetooth/public/interfaces/device.mojom
+++ b/device/bluetooth/public/interfaces/device.mojom
@@ -4,10 +4,16 @@
 
 module bluetooth.mojom;
 
+// TODO(crbug.com/657632): Remove when numerical values can be optional.
+struct RSSIWrapper {

[ortuno, 2016/10/19 23:19:19]

I wish we had an Optional<> in javascript :/

[mbrunson, 2016/10/20 00:33:51]

Yeah... I think that's planned for ES8. I think the closest we get now is
overloading valueOf or toString mixed with funky getters and setters...eww. 

+  int8 value;
+};
+
 struct DeviceInfo {
   string? name;
   string name_for_display;
   string address;
+  RSSIWrapper? rssi;
 };
 
 interface Device {