Add connecting/connectable to bluetooth.Device.

extensions/common/api/bluetooth.idl

Index: extensions/common/api/bluetooth.idl
diff --git a/extensions/common/api/bluetooth.idl b/extensions/common/api/bluetooth.idl
index 134c04745e2763876d6ac4ef28e0640505db9b32..b110c488d16a823991bc0b6633dca75274a79f37 100644
--- a/extensions/common/api/bluetooth.idl
+++ b/extensions/common/api/bluetooth.idl
@@ -66,6 +66,12 @@ namespace bluetooth {
     // Indicates whether the device is currently connected to the system.
     boolean? connected;
 
+    // Indicates whether the device is currently connecting to the system.
+    boolean? connecting;

[Devlin, 2015/11/05 19:27:58]

It's a shame we're adding so many of these, since it seems like there's a lot of
overlap (connected or connecting implies connectable, connected implies not
connecting, etc).  Ideally, these (and maybe paired) probably would have been a
single enum.  Unfortunately, the ship has probably sailed on that.

That said, what's the concrete use case for these?  I don't actually see a
"connect" method or anything...

If this change is only advantageous for the private API, we shouldn't be putting
it here (and can instead do something like getDeviceStatus as a private API
function).

[stevenjb, 2015/11/05 19:37:54]

paired/connecting/connected could theoretically be combined, but as you mention
it would break backwards compatibility, and frankly, based on my experience with
the networking UI, enums are overrated.

The complete state is useful independent of the private API. 'connecting' in
particular would be useful for showing the status. 'connectable' slightly less
so, but it hardly seems worth the added complexity of adding a separate 'Status'
type (which I think would be very confusing) just for that.

+
+    // Indicates whether the device is connectable.
+    boolean? connectable;
+
     // UUIDs of protocols, profiles and services advertised by the device.
     // For classic Bluetooth devices, this list is obtained from EIR data and
     // SDP tables. For Low Energy devices, this list is obtained from AD and