[bluetooth] Add Winrt Fakes for LE Advertisements

This change adds empty fake implementations for WinRT LE Advertisements.
These fakes will be required in an upcoming CL that implements listening
to LE Advertisements for Winrt. So far, these are merely stubs and don't
provide any functionality.

Bug: 821766
Change-Id: Icf98eacb0f3cf6085c3031b12ca7282c98f1f46e
Reviewed-on: https://chromium-review.googlesource.com/1066060
Commit-Queue: Jan Wilken Dörrie <[email protected]>
Reviewed-by: Reilly Grant <[email protected]>
Cr-Commit-Position: refs/heads/master@{#564035}
7 files changed