cc: Move LayerEvictionTileIterator to a separate file and make it a queue

In line with LayerRasterTileIterator patch, this patch removes
PictureLayerImpl::LayerEvictionTileIterator, moves it to a separate
file, renames it to TilingSetEvictionQueue, makes its functionality be
more queue-like instead of iterator-like and merges
PictureLayerTiling::TilingEvictionTileIterator into it (as those two
iterators were so tightly coupled).

Also, this patch adds a PLI::CreateEvictionQueue to get a eviction queue
for the layer.

This hides a bit more details of PLTS from PLI and avoid duplicating
eviction category handling in multiple different iterator classes.

Review URL: https://codereview.chromium.org/741683003

Cr-Commit-Position: refs/heads/master@{#305972}
14 files changed