Restore Cobalt customizations

b/283570016

third_party/libxml/BUILD.gn

@@ -4,6 +4,9 @@
 
 # Define an "os_include" variable that points at the OS-specific generated
 # headers.  These were generated by running the configure script offline.
+if (use_cobalt_customizations) {
+  os_include = "starboard"
+} else
 if (is_linux || is_chromeos || is_android || is_nacl || is_fuchsia) {
   os_include = "linux"
 } else if (is_apple) {
@@ -66,6 +69,12 @@ config("libxml_warnings") {
       # TODO(hans): See if we can fix upstream (http://crbug.com/763944).
       "-Wno-enum-compare",
     ]
+    if (is_clang_16 && use_cobalt_customizations) {
+      cflags += [
+        # xmlschemas.c variable 'count' set but not used
+        "-Wno-unused-but-set-variable",
+      ]
+    }
   } else if (is_linux || is_chromeos) {
     cflags = [
       # gcc spits out a bunch of warnings about passing too many arguments to
@@ -75,6 +84,7 @@ config("libxml_warnings") {
   }
 }
 
+if (!use_cobalt_customizations) {  # exclude libraries "xml_reader" and "xml_writer"
 static_library("xml_reader") {
   # Do not expand this visibility list without first consulting with the
   # Security Team.
@@ -111,6 +121,7 @@ static_library("xml_writer") {
   ]
   configs += [ ":libxml_config" ]
 }
+}  # exclude libraries "xml_reader" and "xml_writer"
 
 static_library("libxml_utils") {
   # Do not expand this visibility list without first consulting with the
@@ -144,6 +155,15 @@ static_library("libxml") {
     "//third_party/libxslt",
     "//third_party/maldoca/*",
   ]
+  if (use_cobalt_customizations) {
+    visibility += [
+      "//base/test:test_support",
+      "//cobalt/base",
+      "//cobalt/dom_parser",
+      "//cobalt/renderer/rasterizer/skia/skia",
+      "//components/update_client",
+    ]
+  }
   if (is_ios) {
     foreach(tgt, ios_libxml_visibility_additions) {
       visibility += [ "//ios_internal/$tgt" ]
@@ -275,7 +295,9 @@ static_library("libxml") {
     "src/xzlib.h",
   ]
 
+if (!use_cobalt_customizations) {
   configs -= [ "//build/config/compiler:chromium_code" ]
+}
   configs += [
     "//build/config/compiler:no_chromium_code",