Make CPDF_TextStateData private to CPDF_TextState.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 1223ef63b97a2f3c600a07cb6f4066974f1cefa5..cb7ec8d55650e84b0c1503e74dda44e14540441a 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -442,8 +442,6 @@ static_library("fpdfapi") {
     "core/fpdfapi/fpdf_page/cpdf_shadingpattern.h",
     "core/fpdfapi/fpdf_page/cpdf_textobject.cpp",
     "core/fpdfapi/fpdf_page/cpdf_textstate.cpp",
-    "core/fpdfapi/fpdf_page/cpdf_textstate.h",
-    "core/fpdfapi/fpdf_page/cpdf_textstatedata.cpp",
     "core/fpdfapi/fpdf_page/cpdf_tilingpattern.cpp",
     "core/fpdfapi/fpdf_page/cpdf_tilingpattern.h",
     "core/fpdfapi/fpdf_page/fpdf_page_colors.cpp",
@@ -466,7 +464,7 @@ static_library("fpdfapi") {
     "core/fpdfapi/fpdf_page/include/cpdf_pathobject.h",
     "core/fpdfapi/fpdf_page/include/cpdf_shadingobject.h",
     "core/fpdfapi/fpdf_page/include/cpdf_textobject.h",
-    "core/fpdfapi/fpdf_page/include/cpdf_textstatedata.h",
+    "core/fpdfapi/fpdf_page/include/cpdf_textstate.h",
     "core/fpdfapi/fpdf_page/pageint.h",
     "core/fpdfapi/fpdf_parser/cfdf_document.cpp",
     "core/fpdfapi/fpdf_parser/cpdf_array.cpp",