Hide AXPlatformNode on ChromeOS.

ui/accessibility/BUILD.gn

Index: ui/accessibility/BUILD.gn
diff --git a/ui/accessibility/BUILD.gn b/ui/accessibility/BUILD.gn
index 06a95cc9e6e5f65a7051eda4a44e79ed95c502e4..b13406721832b4118e20ce6b49ffe88e510eb164 100644
--- a/ui/accessibility/BUILD.gn
+++ b/ui/accessibility/BUILD.gn
@@ -8,6 +8,7 @@ import("//build/config/ui.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//tools/json_schema_compiler/json_schema_api.gni")
+import("//ui/base/ui_features.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
@@ -49,17 +50,24 @@ component("accessibility") {
     "ax_tree_update.h",
     "platform/ax_android_constants.cc",
     "platform/ax_android_constants.h",
-    "platform/ax_platform_node.cc",
-    "platform/ax_platform_node.h",
-    "platform/ax_platform_node_base.cc",
-    "platform/ax_platform_node_base.h",
-    "platform/ax_platform_node_delegate.h",
-    "platform/ax_platform_node_mac.h",
-    "platform/ax_platform_node_mac.mm",
-    "platform/ax_platform_node_win.cc",
-    "platform/ax_platform_node_win.h",
+    "platform/ax_platform_unique_id.cc",
+    "platform/ax_platform_unique_id.h",
   ]
 
+  if (has_native_accessibility) {
+    sources += [
+      "platform/ax_platform_node.cc",
+      "platform/ax_platform_node.h",
+      "platform/ax_platform_node_base.cc",
+      "platform/ax_platform_node_base.h",
+      "platform/ax_platform_node_delegate.h",
+      "platform/ax_platform_node_mac.h",
+      "platform/ax_platform_node_mac.mm",
+      "platform/ax_platform_node_win.cc",
+      "platform/ax_platform_node_win.h",
+    ]
+  }
+
   defines = [ "ACCESSIBILITY_IMPLEMENTATION" ]
 
   public_deps = [
@@ -116,12 +124,17 @@ if (is_android) {
 
 static_library("test_support") {
   sources = [
-    "platform/test_ax_node_wrapper.cc",
-    "platform/test_ax_node_wrapper.h",
     "tree_generator.cc",
     "tree_generator.h",
   ]
 
+  if (is_win) {
+    sources += [
+      "platform/test_ax_node_wrapper.cc",
+      "platform/test_ax_node_wrapper.h",
+    ]
+  }
+
   deps = [
     ":accessibility",
   ]