Revert of Revert of [Easy Unlock] Port the BluetoothConnectionFinder class to native code.

components/proximity_auth/bluetooth_connection.cc

Index: components/proximity_auth/bluetooth_connection.cc
diff --git a/components/proximity_auth/bluetooth_connection.cc b/components/proximity_auth/bluetooth_connection.cc
index fdc7103219096d24372cc73747949a532a922bd2..d5a2b653101ebbb1d4ca2619a3dc16b8f538d2a2 100644
--- a/components/proximity_auth/bluetooth_connection.cc
+++ b/components/proximity_auth/bluetooth_connection.cc
@@ -120,6 +120,8 @@
   if (!bluetooth_device) {
     VLOG(1) << "[BC] Device with address " << address
             << " is not known to the system Bluetooth daemon.";
+    // TOOD(isherman): Optimistically attempt to seek the device and connect
+    // anyway, as was previously implemented in BluetoothConnectionFinder.
     Disconnect();
     return;
   }