Reland of Unify some code

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index a54f6e401870960f8b3f6bd20d8a2be8661859f9..0cf5f54c77121fa8ef96c15b30c1f8560bdf7c50 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -500,6 +500,8 @@ static_library("fpdfapi") {
     "core/fpdfapi/parser/cpdf_hint_tables.h",
     "core/fpdfapi/parser/cpdf_indirect_object_holder.cpp",
     "core/fpdfapi/parser/cpdf_indirect_object_holder.h",
+    "core/fpdfapi/parser/cpdf_linearized.cpp",
+    "core/fpdfapi/parser/cpdf_linearized.h",
     "core/fpdfapi/parser/cpdf_name.cpp",
     "core/fpdfapi/parser/cpdf_name.h",
     "core/fpdfapi/parser/cpdf_null.cpp",