Major rearchitecture of SkSL parsing, focused on improving performance.

Bug: skia:
Change-Id: I83e3a094d26085fc4d586e5d2581e0d61c55634e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/145080
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/src/sksl/SkSLStringStream.h b/src/sksl/SkSLStringStream.h
index 8de1d40..d34d08d 100644
--- a/src/sksl/SkSLStringStream.h
+++ b/src/sksl/SkSLStringStream.h
@@ -9,6 +9,7 @@
 #define SKSL_STRINGSTREAM
 
 #include "src/sksl/SkSLOutputStream.h"
+#include "src/sksl/SkSLString.h"
 
 #ifdef SKSL_STANDALONE