Revert "Revert "Switch to the new SkSL lexer.""

This reverts commit 358515491a0d6891e6a709688a30ad087df1beb1.

Bug: skia:
Change-Id: I013fac0ed83774d8ae7c6ee6819045cab37f5e97
Reviewed-on: https://skia-review.googlesource.com/45180
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/sksl/ast/SkSLASTStatement.h b/src/sksl/ast/SkSLASTStatement.h
index 1989a1f..c22a2fb 100644
--- a/src/sksl/ast/SkSLASTStatement.h
+++ b/src/sksl/ast/SkSLASTStatement.h
@@ -33,8 +33,8 @@
         kDiscard_Kind
     };
 
-    ASTStatement(Position position, Kind kind)
-    : INHERITED(position)
+    ASTStatement(int offset, Kind kind)
+    : INHERITED(offset)
     , fKind(kind) {}
 
     Kind fKind;