This will allow us to start reasoning about more global config options in
Grappler. For example, it will allow us to move XLA functionalization rewrites
into Grappler, because we'll know when JIT optimization has been turned on.
We'll also be able to selectively disable particular grappler rewrites when
JIT optimization is on.
Additional changes:
* PartitionedCall now accepts a ConfigProto instead of a RewriterConfig
* Eager context now passes the entire ConfigProto through.
PiperOrigin-RevId: 221460335
