Fix missing computeIfAbsent() method in L_MR1 and M

Replace ConcurrentHashMap#computeIfAbsent() with containsKey() and put()
since computeIfAbsent() is added in API level 24.

Bug: 158846265
Test: Build

Signed-off-by: Taesu Lee <taesu82.lee@samsung.com>
Change-Id: I3c43f0d7b1f289f0442c9359de4f099217244387
1 file changed