Fix typo in BUILD.gn at f040890.

TBR=brucedawson@chromium.org

Review URL: https://codereview.chromium.org/1784243007 .

BUILD.gn

diff --git a/BUILD.gn b/BUILD.gn
index 4c5fbac..402fe23 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -351,6 +351,8 @@
     "core/src/fpdfapi/fpdf_parser/cfdf_document.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_array.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_boolean.cpp",
+    "core/src/fpdfapi/fpdf_parser/cpdf_data_avail.cpp",
+    "core/src/fpdfapi/fpdf_parser/cpdf_data_avail.h",
     "core/src/fpdfapi/fpdf_parser/cpdf_dictionary.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_document.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp",
@@ -371,8 +373,6 @@
     "core/src/fpdfapi/fpdf_parser/cpdf_string.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.h",
-    "core/src/fpdfapi/fpdf_parser/fpdf_data_avail.cpp",
-    "core/src/fpdfapi/fpdf_parser/fpdf_data_avail.h",
     "core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp",
     "core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp",
     "core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.h",