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/SkSLASTWhileStatement.h b/src/sksl/ast/SkSLASTWhileStatement.h
index e63c502..c0da0af 100644
--- a/src/sksl/ast/SkSLASTWhileStatement.h
+++ b/src/sksl/ast/SkSLASTWhileStatement.h
@@ -16,9 +16,9 @@
  * A 'while' statement.
  */
 struct ASTWhileStatement : public ASTStatement {
-    ASTWhileStatement(Position position, std::unique_ptr<ASTExpression> test,
+    ASTWhileStatement(int offset, std::unique_ptr<ASTExpression> test,
                       std::unique_ptr<ASTStatement> statement)
-    : INHERITED(position, kWhile_Kind)
+    : INHERITED(offset, kWhile_Kind)
     , fTest(std::move(test))
     , fStatement(std::move(statement)) {}