Fix gn build.

TBR=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/338553002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21843 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

BUILD.gn

@@ -365,6 +365,8 @@ source_set("v8_base") {
     "src/assembler.h",
     "src/assert-scope.h",
     "src/assert-scope.cc",
+    "src/ast-value-factory.cc",
+    "src/ast-value-factory.h",
     "src/ast.cc",
     "src/ast.h",
     "src/bignum-dtoa.cc",