Revert "Suppress some deprecation warnings on Windows (flutter#16416)"

This reverts commit 230c6b4.

Author: NoamDev

fml/BUILD.gn

@@ -202,11 +202,6 @@ source_set("fml") {
       "platform/win/paths_win.cc",
       "platform/win/wstring_conversion.h",
     ]
-
-    if (is_win) {
-      # For wstring_conversion. See issue #50053.
-      defines = [ "_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING" ]
-    }
   } else {
     sources += [
       "platform/posix/file_posix.cc",

shell/platform/common/cpp/BUILD.gn

@@ -53,11 +53,6 @@ source_set("common_cpp") {
   # won't have a JSON dependency.
   defines = [ "USE_RAPID_JSON" ]
   deps += [ "//third_party/rapidjson" ]
-
-  if (is_win) {
-    # For wstring_conversion. See issue #50053.
-    defines += [ "_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING" ]
-  }
 }
 
 copy("publish_headers") {

third_party/txt/BUILD.gn

@@ -28,14 +28,6 @@ config("txt_config") {
   include_dirs = [ "src" ]
 }
 
-config("allow_posix_names") {
-  if (is_win && is_clang) {
-    # POSIX names of many functions are marked deprecated by default;
-    # disable that since they are used for cross-platform compatibility.
-    defines = [ "_CRT_NONSTDC_NO_DEPRECATE" ]
-  }
-}
-
 source_set("txt") {
   defines = []
   if (flutter_use_fontconfig) {
@@ -304,8 +296,6 @@ executable("txt_unittests") {
     ]
   }
 
-  configs += [ ":allow_posix_names" ]
-
   deps = [
            ":txt",
            ":txt_test_utils",