Delete SkSL::Compiler copy constructor and assignment operator

Another fix for Windows DLL builds. This is basically the issue from
crbug.com/770771 - we have a vector<unique_ptr>, and unique_ptr does
not allow copying or assignment. For an exported (SK_API) class, those
members will be auto-generated unless they're explicitly deleted.

Change-Id: I5764ecf0528f28cc3c201127b51574ad41841325
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/207220
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
1 file changed