I've written some new hashtable interfaces that should be easier to use,
and I've been trying to roll them out bit by bit, hopefully replacing
SkTDynamicHash, SkTMultiMap, SkTHashCache, etc.
This turns the cache in GrGLCaps::readPixelsSupported() into an SkTHashMap,
mapping the format key to a bool. Functionally, it's the same.
BUG=skia:
Review URL: https://codereview.chromium.org/948473002
SkTHashTable is very similar to SkTDynamicHash, except it's generalized to support non-pointer value types.
It doesn't support remove(), just to keep things simple (it's not hard to add).
Instead of an iterator, it has foreach(), again, to keep things simple.
SkTHashMap<K,V> and SkTHashSet<T> build a friendlier experience on top of SkTHashTable.
BUG=skia:
Review URL: https://codereview.chromium.org/925613002
