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

chrome/browser/chromeos/system/input_device_settings_impl_x11.cc

Index: chrome/browser/chromeos/system/input_device_settings_impl_x11.cc
diff --git a/chrome/browser/chromeos/system/input_device_settings_impl_x11.cc b/chrome/browser/chromeos/system/input_device_settings_impl_x11.cc
index 79d108edefbcd64e0dcbec0d6f1ec99b596ed504..fa173be41c79c19fcafdfa485dc474667a900857 100644
--- a/chrome/browser/chromeos/system/input_device_settings_impl_x11.cc
+++ b/chrome/browser/chromeos/system/input_device_settings_impl_x11.cc
@@ -22,6 +22,7 @@
 #include "base/sys_info.h"
 #include "base/task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/chromeos/system/fake_input_device_settings.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/events/base_event_utils.h"
 #include "ui/events/devices/x11/device_data_manager_x11.h"
@@ -35,7 +36,7 @@ namespace system {
 namespace {
 
 InputDeviceSettings* g_instance = nullptr;
-InputDeviceSettings* g_test_instance = nullptr;
+FakeInputDeviceSettings* g_test_instance = nullptr;
 
 const char kDeviceTypeTouchpad[] = "touchpad";
 const char kDeviceTypeMouse[] = "mouse";
@@ -350,8 +351,15 @@ 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;