tonihei dcc2f9bd67 Add meta data class for AbstractConcatenatedTimeline.
(Preparation for GitHub issue #1706)

AbstractConcatenatedTimeline repeatly calls methods of its implementation to
query a specific child timeline. This may be inefficient if the implementation
repeatly executes the same code to find the timeline.

Changed the class such that it now queries all information at once using a meta
data class. As all methods need at least two of four variables anyway, this
doesn't generate unnecessary overhead.

Also generified the UID for the child indices to allow new implementations to
use some other UID besides the index.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=158711979
2017-06-13 13:14:01 +01:00
..