Migrate ModifiersPool into the context.

The IRGenerator no longer owns the pool of modifiers; they are now
available to any function that has a Context.

Change-Id: I4f2f37ae5e06966bed00107b0483b42b07a454d8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/404237
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/sksl/SkSLRehydrator.cpp b/src/sksl/SkSLRehydrator.cpp
index 44fba39..378120a 100644
--- a/src/sksl/SkSLRehydrator.cpp
+++ b/src/sksl/SkSLRehydrator.cpp
@@ -77,11 +77,9 @@
     std::shared_ptr<SymbolTable> fOldSymbols;
 };
 
-Rehydrator::Rehydrator(const Context* context, ModifiersPool* modifiers,
-                       std::shared_ptr<SymbolTable> symbolTable,
+Rehydrator::Rehydrator(const Context* context,  std::shared_ptr<SymbolTable> symbolTable,
                        const uint8_t* src, size_t length)
                 : fContext(*context)
-                , fModifiers(*modifiers)
                 , fSymbolTable(std::move(symbolTable))
                 , fStart(src)
     SkDEBUGCODE(, fEnd(fStart + length)) {