Move node information to SkStrikeCache

Move all the information for handling nodes into
SkStrikeCache. Having all the cache organization
in SkStrikeCache will localize all the Chrome
pinning machinery to this class.

BUG=skia:7515

Change-Id: I5bc5488ddfe1806d62927d13148af36dac08eae9
Reviewed-on: https://skia-review.googlesource.com/121888
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
5 files changed