Use :: prefix to distinguish between ::media_router::prefs and ::prefs

There are two namespaces named prefs in scope inside media_router code:
The global ::prefs namespace and the local ::media_router::prefs namespace.

If both namespaces are known to the compiler, as happens in jumbo builds,
then the name lookup will be ambigious and the compiler will fail to
compile the code.

Bug: 803406
Change-Id: Ib4be547ffe1ba7a790c2003fd54bd091935c378e
Commit-Queue: mark a. foltz <>
Reviewed-by: mark a. foltz <>
Cr-Commit-Position: refs/heads/master@{#575379}
1 file changed