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

chrome/browser/chromeos/system/input_device_settings.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_SYSTEM_INPUT_DEVICE_SETTINGS_H_
 #define CHROME_BROWSER_CHROMEOS_SYSTEM_INPUT_DEVICE_SETTINGS_H_
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "chromeos/chromeos_export.h"
 
 class PrefRegistrySimple;
 
 namespace chromeos {
 namespace system {
 
+class FakeInputDeviceSettings;
 class InputDeviceSettings;
 
 namespace internal {
 
 // Objects of this class are intended to store values of type T, but might have
 // "unset" state. Object will be in "unset" state until Set is called first
 // time.
 template <typename T>
 class Optional {
  public:
@@ skipping 126 matching lines @@
 // Interface for configuring input device settings.
 class CHROMEOS_EXPORT InputDeviceSettings {
  public:
   typedef base::Callback<void(bool)> DeviceExistsCallback;
 
   virtual ~InputDeviceSettings() {}
 
   // Returns current instance of InputDeviceSettings.
   static InputDeviceSettings* Get();
 
+  // Returns test instance of InputDeviceSettings.
+  static FakeInputDeviceSettings* GetForTesting();

[stevenjb, 2016/06/30 00:17:30]

See my comment in the other CL, this should be merged into Get(). Let me know if
that is more problematic than I imagine.

[michaelpg, 2016/07/01 22:01:48]

I would have to git try that to make sure it doesn't break anything else in
CrOS.

But the reason I made GetForTesting() was to use the setters (eg
set_mouse_exists)
which are specific to FakeInputDeviceSettings.

I could create a new FakeInputDeviceSettings and use SetSettingsForTesting in
device_emulator_message_handler.cc, but then opening chrome://device-emulator
would reset those settings, which doesn't make sense.

[stevenjb, 2016/07/02 00:28:26]

I agree we shouldn't create a new / additional FakeInputDeviceSettings. That
should be transparent.

Take a look at FakeShillServiceClient::GetTestInterface. This is a model we have
used to allow setting of fake properties without having to expose the details of
the fake class to callers. The fake implementation will return a valid fake
interface and the real implementation will return a null interface.

[michaelpg, 2016/07/07 22:16:54]

Done, created InputDeviceSettings::FakeInterface. Definitely simpler.

+
   // Replaces current instance with |test_settings|. Takes ownership of
   // |test_settings|. Default implementation could be returned back by passing
   // NULL to this method.
-  static void SetSettingsForTesting(InputDeviceSettings* test_settings);
+  static void SetSettingsForTesting(FakeInputDeviceSettings* test_settings);
 
   // Returns true if UI should implement enhanced keyboard support for cases
   // where other input devices like mouse are absent.
   static bool ForceKeyboardDrivenUINavigation();
 
   // Registers local pref names for touchpad and touch screen statuses.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
   void InitTouchDevicesStatusFromLocalPrefs();
 
   // Toggles the status of Touchscreen/Touchpad on or off and updates the local
   // prefs.
   void ToggleTouchscreen();
   void ToggleTouchpad();
 
-  // Calls |callback| asynchronously after determining if a touchpad is
-  // connected.
+  // Calls |callback|, possibly asynchronously, after determining if a touchpad
+  // is connected.
   virtual void TouchpadExists(const DeviceExistsCallback& callback) = 0;
 
   // Updates several touchpad settings at a time. Updates only settings that
   // are set in |settings| object. It is more efficient to use this method to
   // update several settings then calling Set* methods one by one.
   virtual void UpdateTouchpadSettings(const TouchpadSettings& settings) = 0;
 
   // Sets the touchpad sensitivity in the range [kMinPointerSensitivity,
   // kMaxPointerSensitivity].
   virtual void SetTouchpadSensitivity(int value) = 0;
 
   // Turns tap to click on/off.
   virtual void SetTapToClick(bool enabled) = 0;
 
   // Switch for three-finger click.
   virtual void SetThreeFingerClick(bool enabled) = 0;
 
   // Turns tap-dragging on/off.
   virtual void SetTapDragging(bool enabled) = 0;
 
   // Turns natural scrolling on/off for all devices except wheel mice
   virtual void SetNaturalScroll(bool enabled) = 0;
 
-  // Calls |callback| asynchronously after determining if a mouse is connected.
+  // Calls |callback|, possibly asynchronously, after determining if a mouse is
+  // connected.
   virtual void MouseExists(const DeviceExistsCallback& callback) = 0;
 
   // Updates several mouse settings at a time. Updates only settings that
   // are set in |settings| object. It is more efficient to use this method to
   // update several settings then calling Set* methods one by one.
   virtual void UpdateMouseSettings(const MouseSettings& settings) = 0;
 
   // Sets the mouse sensitivity in the range [kMinPointerSensitivity,
   // kMaxPointerSensitivity].
   virtual void SetMouseSensitivity(int value) = 0;
 
   // Sets the primary mouse button to the right button if |right| is true.
   virtual void SetPrimaryButtonRight(bool right) = 0;
 
   // Reapplies previously set touchpad settings.
   virtual void ReapplyTouchpadSettings() = 0;
 
   // Reapplies previously set mouse settings.
   virtual void ReapplyMouseSettings() = 0;
 
  private:
   virtual void SetInternalTouchpadEnabled(bool enabled) {}
   virtual void SetTouchscreensEnabled(bool enabled) {}
 };
 
 }  // namespace system
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_INPUT_DEVICE_SETTINGS_H_