Simplify code

Use DefaultKeyedVector::valueFor to avoid extra test
Make local variables as local as possible
No double parentheses
No typedef for single use
No parentheses around indirect function call
No AudioFlinger:: prefix when not needed
Remove unnecessary casts
Remove block with only one line

Saves 128 bytes

Change-Id: I3a87430eeb01b81e7b81a1c38f6fdd3274ec48f3