Use fake Input Device Settings with chrome://device-emulator

chrome/browser/chromeos/system/input_device_settings_impl_ozone.cc

Index: chrome/browser/chromeos/system/input_device_settings_impl_ozone.cc
diff --git a/chrome/browser/chromeos/system/input_device_settings_impl_ozone.cc b/chrome/browser/chromeos/system/input_device_settings_impl_ozone.cc
index a75e6d979137079126dd58e5df8cf47092545e99..e8f0c1f6e830afa425c5bf0ae979797cefe5b4b5 100644
--- a/chrome/browser/chromeos/system/input_device_settings_impl_ozone.cc
+++ b/chrome/browser/chromeos/system/input_device_settings_impl_ozone.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/chromeos/system/input_device_settings.h"
 
 #include "base/macros.h"
+#include "chrome/browser/chromeos/system/fake_input_device_settings.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/ozone/public/input_controller.h"
 #include "ui/ozone/public/ozone_platform.h"
@@ -19,7 +20,7 @@ namespace system {
 namespace {
 
 InputDeviceSettings* g_instance = nullptr;
-InputDeviceSettings* g_test_instance = nullptr;
+FakeInputDeviceSettings* g_test_instance = nullptr;
 
 std::unique_ptr<ui::InputController> CreateStubInputControllerIfNecessary() {
 #if defined(MOJO_SHELL_CLIENT)
@@ -170,8 +171,15 @@ InputDeviceSettings* InputDeviceSettings::Get() {
 }
 
 // static
+FakeInputDeviceSettings* InputDeviceSettings::GetForTesting() {
+  if (!g_test_instance)
+    g_test_instance = new FakeInputDeviceSettings();
+  return g_test_instance;
+}
+
+// static
 void InputDeviceSettings::SetSettingsForTesting(
-    InputDeviceSettings* test_settings) {
+    FakeInputDeviceSettings* test_settings) {
   if (g_test_instance == test_settings)
     return;
   delete g_test_instance;