Force U.S. English keyboard layout for TextfieldTest.KeysWithModifiersTest

ui/events/BUILD.gn

Index: ui/events/BUILD.gn
diff --git a/ui/events/BUILD.gn b/ui/events/BUILD.gn
index dd9c9ff36daf25394aa5ea2dd52ac752f0f9244b..e1bd932291dc6b32cf8b11357b36898262c10048 100644
--- a/ui/events/BUILD.gn
+++ b/ui/events/BUILD.gn
@@ -276,6 +276,10 @@ static_library("test_support") {
     "test/event_generator.h",
     "test/events_test_utils.cc",
     "test/events_test_utils.h",
+    "test/keyboard_layout.cc",
+    "test/keyboard_layout.h",
+    "test/keyboard_layout_mac.cc",
+    "test/keyboard_layout_win.cc",
     "test/motion_event_test_utils.cc",
     "test/motion_event_test_utils.h",
     "test/platform_event_source_test_api.cc",
@@ -313,6 +317,10 @@ static_library("test_support") {
     ]
   }
 
+  if (is_mac) {
+    libs = [ "Carbon.framework" ]
+  }
+
   if (use_x11) {
     sources += [
       "test/events_test_utils_x11.cc",