Update Observable to OpenJDK8u60.

Reverted comment parts of fbabe73723c24c38cbfd6429387dae5e6478513f
Added missing Android-changed comment for the behavior parts of
that CL.

This CL does not change behavior.

Test: treehugger build succeeds
Bug: 29935305

Change-Id: I40d19bd4357eadc1016df4ab505c6349d516944b
1 file changed