Memory hog: ImmutableList is appropriate here

There is no need to allocate two objects. Let's optimize for memory, as
these objects may be retained for a long time.

Change-Id: I73ba2b95e6e80876ba115a751b69be801da39063
Signed-off-by: Robert Varga <rovarga@cisco.com>
Merge "Memory hog: ImmutableList is appropriate here"