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..40b2d2790b19b1016326753a03b806a2c32f8cf3 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",
@@ -310,6 +314,7 @@ static_library("test_support") {
     sources -= [
       "test/cocoa_test_event_utils.h",
       "test/cocoa_test_event_utils.mm",
+      "test/keyboard_layout_mac.cc",
     ]
   }