diff --git a/core/fpdfapi/font/cpdf_cidfont.cpp b/core/fpdfapi/font/cpdf_cidfont.cpp
index d16be65..0717795 100644
--- a/core/fpdfapi/font/cpdf_cidfont.cpp
+++ b/core/fpdfapi/font/cpdf_cidfont.cpp
@@ -24,7 +24,6 @@
 #include "core/fxcrt/fx_codepage.h"
 #include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_safe_types.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/fx_unicode.h"
 #include "core/fxcrt/stl_util.h"
 #include "core/fxge/fx_font.h"
diff --git a/core/fpdfapi/page/cpdf_colorspace.h b/core/fpdfapi/page/cpdf_colorspace.h
index 543ca2e..3e9bd9c 100644
--- a/core/fpdfapi/page/cpdf_colorspace.h
+++ b/core/fpdfapi/page/cpdf_colorspace.h
@@ -7,6 +7,9 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_COLORSPACE_H_
 #define CORE_FPDFAPI_PAGE_CPDF_COLORSPACE_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <array>
 #include <memory>
 #include <set>
@@ -14,7 +17,6 @@
 
 #include "core/fpdfapi/page/cpdf_pattern.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/observed_ptr.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
diff --git a/core/fpdfapi/page/cpdf_colorstate.h b/core/fpdfapi/page/cpdf_colorstate.h
index 7b4a166..49ce09d 100644
--- a/core/fpdfapi/page/cpdf_colorstate.h
+++ b/core/fpdfapi/page/cpdf_colorstate.h
@@ -10,12 +10,10 @@
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_color.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/shared_copy_on_write.h"
 #include "core/fxge/dib/fx_dib.h"
 
-class CPDF_Color;
 class CPDF_ColorSpace;
 class CPDF_Pattern;
 
diff --git a/core/fpdfapi/page/cpdf_contentmarkitem.h b/core/fpdfapi/page/cpdf_contentmarkitem.h
index a13339d..58743f1 100644
--- a/core/fpdfapi/page/cpdf_contentmarkitem.h
+++ b/core/fpdfapi/page/cpdf_contentmarkitem.h
@@ -8,7 +8,6 @@
 #define CORE_FPDFAPI_PAGE_CPDF_CONTENTMARKITEM_H_
 
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Dictionary;
diff --git a/core/fpdfapi/page/cpdf_contentmarks.h b/core/fpdfapi/page/cpdf_contentmarks.h
index 7bb25ec..d13dc77 100644
--- a/core/fpdfapi/page/cpdf_contentmarks.h
+++ b/core/fpdfapi/page/cpdf_contentmarks.h
@@ -7,11 +7,12 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_CONTENTMARKS_H_
 #define CORE_FPDFAPI_PAGE_CPDF_CONTENTMARKS_H_
 
+#include <stddef.h>
+
 #include <memory>
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_contentmarkitem.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Dictionary;
diff --git a/core/fpdfapi/page/cpdf_image.h b/core/fpdfapi/page/cpdf_image.h
index d725f5f..4af2b68 100644
--- a/core/fpdfapi/page/cpdf_image.h
+++ b/core/fpdfapi/page/cpdf_image.h
@@ -7,8 +7,9 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_IMAGE_H_
 #define CORE_FPDFAPI_PAGE_CPDF_IMAGE_H_
 
+#include <stdint.h>
+
 #include "core/fpdfapi/page/cpdf_colorspace.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
 #include "third_party/base/span.h"
diff --git a/core/fpdfapi/page/cpdf_meshstream.h b/core/fpdfapi/page/cpdf_meshstream.h
index a152ecb..e012b52 100644
--- a/core/fpdfapi/page/cpdf_meshstream.h
+++ b/core/fpdfapi/page/cpdf_meshstream.h
@@ -7,13 +7,14 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_MESHSTREAM_H_
 #define CORE_FPDFAPI_PAGE_CPDF_MESHSTREAM_H_
 
+#include <stdint.h>
+
 #include <memory>
 #include <tuple>
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_shadingpattern.h"
 #include "core/fxcrt/cfx_bitstream.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_StreamAcc;
diff --git a/core/fpdfapi/page/cpdf_page.h b/core/fpdfapi/page/cpdf_page.h
index cd159cd..9a7eb81 100644
--- a/core/fpdfapi/page/cpdf_page.h
+++ b/core/fpdfapi/page/cpdf_page.h
@@ -13,7 +13,6 @@
 #include "core/fpdfapi/page/cpdf_pageobjectholder.h"
 #include "core/fpdfapi/page/ipdf_page.h"
 #include "core/fxcrt/fx_coordinates.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/observed_ptr.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
diff --git a/core/fpdfapi/page/cpdf_pageobject.h b/core/fpdfapi/page/cpdf_pageobject.h
index a8ce3e9..9142377 100644
--- a/core/fpdfapi/page/cpdf_pageobject.h
+++ b/core/fpdfapi/page/cpdf_pageobject.h
@@ -7,10 +7,11 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_PAGEOBJECT_H_
 #define CORE_FPDFAPI_PAGE_CPDF_PAGEOBJECT_H_
 
+#include <stdint.h>
+
 #include "core/fpdfapi/page/cpdf_contentmarks.h"
 #include "core/fpdfapi/page/cpdf_graphicstates.h"
 #include "core/fxcrt/fx_coordinates.h"
-#include "core/fxcrt/fx_system.h"
 
 class CPDF_FormObject;
 class CPDF_ImageObject;
diff --git a/core/fpdfapi/page/cpdf_pageobjectholder.h b/core/fpdfapi/page/cpdf_pageobjectholder.h
index 3eb976e..91b148b 100644
--- a/core/fpdfapi/page/cpdf_pageobjectholder.h
+++ b/core/fpdfapi/page/cpdf_pageobjectholder.h
@@ -7,6 +7,9 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_PAGEOBJECTHOLDER_H_
 #define CORE_FPDFAPI_PAGE_CPDF_PAGEOBJECTHOLDER_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <deque>
 #include <map>
 #include <memory>
@@ -17,7 +20,6 @@
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
 #include "core/fxge/dib/fx_dib.h"
diff --git a/core/fpdfapi/page/cpdf_path.h b/core/fpdfapi/page/cpdf_path.h
index 774319e..022306b 100644
--- a/core/fpdfapi/page/cpdf_path.h
+++ b/core/fpdfapi/page/cpdf_path.h
@@ -9,7 +9,6 @@
 
 #include <vector>
 
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/shared_copy_on_write.h"
 #include "core/fxge/cfx_path.h"
 
diff --git a/core/fpdfapi/page/cpdf_pathobject.h b/core/fpdfapi/page/cpdf_pathobject.h
index 7ff326c..10c4112 100644
--- a/core/fpdfapi/page/cpdf_pathobject.h
+++ b/core/fpdfapi/page/cpdf_pathobject.h
@@ -7,10 +7,11 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_PATHOBJECT_H_
 #define CORE_FPDFAPI_PAGE_CPDF_PATHOBJECT_H_
 
+#include <stdint.h>
+
 #include "core/fpdfapi/page/cpdf_pageobject.h"
 #include "core/fpdfapi/page/cpdf_path.h"
 #include "core/fxcrt/fx_coordinates.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxge/cfx_fillrenderoptions.h"
 
 class CPDF_PathObject final : public CPDF_PageObject {
diff --git a/core/fpdfapi/page/cpdf_pattern.h b/core/fpdfapi/page/cpdf_pattern.h
index 7e3eb7b..f455f77 100644
--- a/core/fpdfapi/page/cpdf_pattern.h
+++ b/core/fpdfapi/page/cpdf_pattern.h
@@ -8,7 +8,6 @@
 #define CORE_FPDFAPI_PAGE_CPDF_PATTERN_H_
 
 #include "core/fxcrt/fx_coordinates.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/observed_ptr.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
diff --git a/core/fpdfapi/page/cpdf_psengine.h b/core/fpdfapi/page/cpdf_psengine.h
index faf8d94..ac9777b 100644
--- a/core/fpdfapi/page/cpdf_psengine.h
+++ b/core/fpdfapi/page/cpdf_psengine.h
@@ -7,11 +7,13 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_PSENGINE_H_
 #define CORE_FPDFAPI_PAGE_CPDF_PSENGINE_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <memory>
 #include <vector>
 
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "third_party/base/span.h"
 
 class CPDF_PSEngine;
diff --git a/core/fpdfapi/page/cpdf_shadingpattern.h b/core/fpdfapi/page/cpdf_shadingpattern.h
index da45fc1..4e5608b 100644
--- a/core/fpdfapi/page/cpdf_shadingpattern.h
+++ b/core/fpdfapi/page/cpdf_shadingpattern.h
@@ -7,12 +7,13 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_SHADINGPATTERN_H_
 #define CORE_FPDFAPI_PAGE_CPDF_SHADINGPATTERN_H_
 
+#include <stdint.h>
+
 #include <memory>
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_colorspace.h"
 #include "core/fpdfapi/page/cpdf_pattern.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 // Values used in PDFs except for |kInvalidShading| and |kMaxShading|.
diff --git a/core/fpdfapi/page/cpdf_textobject.h b/core/fpdfapi/page/cpdf_textobject.h
index 2fe269f..e607d18 100644
--- a/core/fpdfapi/page/cpdf_textobject.h
+++ b/core/fpdfapi/page/cpdf_textobject.h
@@ -7,12 +7,14 @@
 #ifndef CORE_FPDFAPI_PAGE_CPDF_TEXTOBJECT_H_
 #define CORE_FPDFAPI_PAGE_CPDF_TEXTOBJECT_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <memory>
 #include <vector>
 
 #include "core/fpdfapi/page/cpdf_pageobject.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_TextObject final : public CPDF_PageObject {
diff --git a/core/fpdfapi/page/cpdf_tilingpattern.h b/core/fpdfapi/page/cpdf_tilingpattern.h
index c01671f..94fd7c6 100644
--- a/core/fpdfapi/page/cpdf_tilingpattern.h
+++ b/core/fpdfapi/page/cpdf_tilingpattern.h
@@ -11,7 +11,6 @@
 
 #include "core/fpdfapi/page/cpdf_pattern.h"
 #include "core/fxcrt/fx_coordinates.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Document;
diff --git a/core/fpdfapi/parser/cpdf_boolean.h b/core/fpdfapi/parser/cpdf_boolean.h
index 1b05a24..d2f556d 100644
--- a/core/fpdfapi/parser/cpdf_boolean.h
+++ b/core/fpdfapi/parser/cpdf_boolean.h
@@ -9,7 +9,6 @@
 
 #include "core/fpdfapi/parser/cpdf_object.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Boolean final : public CPDF_Object {
diff --git a/core/fpdfapi/parser/cpdf_cross_ref_table.h b/core/fpdfapi/parser/cpdf_cross_ref_table.h
index 66a51de..c5f004d 100644
--- a/core/fpdfapi/parser/cpdf_cross_ref_table.h
+++ b/core/fpdfapi/parser/cpdf_cross_ref_table.h
@@ -5,10 +5,12 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_CROSS_REF_TABLE_H_
 #define CORE_FPDFAPI_PARSER_CPDF_CROSS_REF_TABLE_H_
 
+#include <stdint.h>
+
 #include <map>
 #include <memory>
 
-#include "core/fxcrt/fx_system.h"
+#include "core/fxcrt/fx_types.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Dictionary;
diff --git a/core/fpdfapi/parser/cpdf_crypto_handler.h b/core/fpdfapi/parser/cpdf_crypto_handler.h
index de94f9e..58410c5 100644
--- a/core/fpdfapi/parser/cpdf_crypto_handler.h
+++ b/core/fpdfapi/parser/cpdf_crypto_handler.h
@@ -7,13 +7,15 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_CRYPTO_HANDLER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_CRYPTO_HANDLER_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <memory>
 
 #include "core/fdrm/fx_crypt.h"
 #include "core/fxcrt/cfx_binarybuf.h"
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "third_party/base/span.h"
 
diff --git a/core/fpdfapi/parser/cpdf_indirect_object_holder.h b/core/fpdfapi/parser/cpdf_indirect_object_holder.h
index 1b1f861..0b3e4df 100644
--- a/core/fpdfapi/parser/cpdf_indirect_object_holder.h
+++ b/core/fpdfapi/parser/cpdf_indirect_object_holder.h
@@ -7,13 +7,14 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_INDIRECT_OBJECT_HOLDER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_INDIRECT_OBJECT_HOLDER_H_
 
+#include <stdint.h>
+
 #include <map>
 #include <memory>
 #include <type_traits>
 #include <utility>
 
 #include "core/fpdfapi/parser/cpdf_object.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/string_pool_template.h"
 #include "core/fxcrt/weak_ptr.h"
diff --git a/core/fpdfapi/parser/cpdf_linearized_header.h b/core/fpdfapi/parser/cpdf_linearized_header.h
index 546e5a9..5329e92 100644
--- a/core/fpdfapi/parser/cpdf_linearized_header.h
+++ b/core/fpdfapi/parser/cpdf_linearized_header.h
@@ -7,9 +7,11 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_LINEARIZED_HEADER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_LINEARIZED_HEADER_H_
 
+#include <stdint.h>
+
 #include <memory>
 
-#include "core/fxcrt/fx_system.h"
+#include "core/fxcrt/fx_types.h"
 
 class CPDF_Dictionary;
 class CPDF_SyntaxParser;
diff --git a/core/fpdfapi/parser/cpdf_number.h b/core/fpdfapi/parser/cpdf_number.h
index 58754ef..bf75bc5 100644
--- a/core/fpdfapi/parser/cpdf_number.h
+++ b/core/fpdfapi/parser/cpdf_number.h
@@ -10,7 +10,6 @@
 #include "core/fpdfapi/parser/cpdf_object.h"
 #include "core/fxcrt/fx_number.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Number final : public CPDF_Object {
diff --git a/core/fpdfapi/parser/cpdf_object.h b/core/fpdfapi/parser/cpdf_object.h
index a6b9136..7bb404a 100644
--- a/core/fpdfapi/parser/cpdf_object.h
+++ b/core/fpdfapi/parser/cpdf_object.h
@@ -7,12 +7,13 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_OBJECT_H_
 #define CORE_FPDFAPI_PARSER_CPDF_OBJECT_H_
 
+#include <stdint.h>
+
 #include <memory>
 #include <set>
 #include <type_traits>
 
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Array;
diff --git a/core/fpdfapi/parser/cpdf_parser.h b/core/fpdfapi/parser/cpdf_parser.h
index a2939cd..b0b24ae 100644
--- a/core/fpdfapi/parser/cpdf_parser.h
+++ b/core/fpdfapi/parser/cpdf_parser.h
@@ -7,6 +7,9 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_PARSER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_PARSER_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <limits>
 #include <map>
 #include <memory>
@@ -16,7 +19,7 @@
 #include "core/fpdfapi/parser/cpdf_cross_ref_table.h"
 #include "core/fpdfapi/parser/cpdf_indirect_object_holder.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
+#include "core/fxcrt/fx_types.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
 
diff --git a/core/fpdfapi/parser/cpdf_security_handler.h b/core/fpdfapi/parser/cpdf_security_handler.h
index 79f5ced..15f2b54 100644
--- a/core/fpdfapi/parser/cpdf_security_handler.h
+++ b/core/fpdfapi/parser/cpdf_security_handler.h
@@ -7,11 +7,13 @@
 #ifndef CORE_FPDFAPI_PARSER_CPDF_SECURITY_HANDLER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_SECURITY_HANDLER_H_
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include <memory>
 
 #include "core/fpdfapi/parser/cpdf_crypto_handler.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 
 class CPDF_Array;
diff --git a/core/fpdfapi/render/cpdf_textrenderer.h b/core/fpdfapi/render/cpdf_textrenderer.h
index 6e9853b..d26e970 100644
--- a/core/fpdfapi/render/cpdf_textrenderer.h
+++ b/core/fpdfapi/render/cpdf_textrenderer.h
@@ -7,9 +7,10 @@
 #ifndef CORE_FPDFAPI_RENDER_CPDF_TEXTRENDERER_H_
 #define CORE_FPDFAPI_RENDER_CPDF_TEXTRENDERER_H_
 
+#include <stdint.h>
+
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxge/dib/fx_dib.h"
 #include "third_party/base/span.h"
 
diff --git a/core/fpdfapi/render/cpdf_type3cache.h b/core/fpdfapi/render/cpdf_type3cache.h
index d7dbbb2..563bd9b 100644
--- a/core/fpdfapi/render/cpdf_type3cache.h
+++ b/core/fpdfapi/render/cpdf_type3cache.h
@@ -7,11 +7,12 @@
 #ifndef CORE_FPDFAPI_RENDER_CPDF_TYPE3CACHE_H_
 #define CORE_FPDFAPI_RENDER_CPDF_TYPE3CACHE_H_
 
+#include <stdint.h>
+
 #include <map>
 #include <memory>
 
 #include "core/fxcrt/fx_string.h"
-#include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/observed_ptr.h"
 #include "core/fxcrt/retain_ptr.h"