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

chrome/browser/chromeos/system/fake_input_device_settings.h

Index: chrome/browser/chromeos/system/fake_input_device_settings.h
diff --git a/chrome/browser/chromeos/system/fake_input_device_settings.h b/chrome/browser/chromeos/system/fake_input_device_settings.h
index 5138454e9c26fb1b2bb3bee1bd6ac0dad0670f27..3da56e80b4528d5f30f7ef137f2e90e3c3f4a8bb 100644
--- a/chrome/browser/chromeos/system/fake_input_device_settings.h
+++ b/chrome/browser/chromeos/system/fake_input_device_settings.h
@@ -13,7 +13,8 @@ namespace chromeos {
 namespace system {
 
 // This fake just memorizes current values of input devices settings.
-class FakeInputDeviceSettings : public InputDeviceSettings {
+class FakeInputDeviceSettings : public InputDeviceSettings,
+                                public InputDeviceSettings::FakeInterface {
  public:
   FakeInputDeviceSettings();
   ~FakeInputDeviceSettings() override;
@@ -32,19 +33,21 @@ class FakeInputDeviceSettings : public InputDeviceSettings {
   void SetNaturalScroll(bool enabled) override;
   void ReapplyTouchpadSettings() override;
   void ReapplyMouseSettings() override;
+  InputDeviceSettings::FakeInterface* GetFakeInterface() override;
 
-  const TouchpadSettings& current_touchpad_settings() const {
-    return current_touchpad_settings_;
-  }
-
-  const MouseSettings& current_mouse_settings() const {
-    return current_mouse_settings_;
-  }
+  // Overridden from InputDeviceSettings::FakeInterface.
+  void set_touchpad_exists(bool exists) override;
+  void set_mouse_exists(bool exists) override;
+  const TouchpadSettings& current_touchpad_settings() const override;
+  const MouseSettings& current_mouse_settings() const override;
 
  private:
   TouchpadSettings current_touchpad_settings_;
   MouseSettings current_mouse_settings_;
 
+  bool touchpad_exists_ = true;
+  bool mouse_exists_ = true;
+
   DISALLOW_COPY_AND_ASSIGN(FakeInputDeviceSettings);
 };