Add hotkey for centering mouse in render window.

Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp

@@ -421,6 +421,16 @@ Common::Vec2 ControllerInterface::GetWindowInputScale() const
     return {1 / ar, 1.f};
 }
 
+void ControllerInterface::SetMouseCenteringRequested(bool center)
+{
+  m_requested_mouse_centering = center;
+}
+
+bool ControllerInterface::IsMouseCenteringRequested() const
+{
+  return m_requested_mouse_centering.load();
+}
+
 // Register a callback to be called when a device is added or removed (as from the input backends'
 // hotplug thread), or when devices are refreshed
 // Returns a handle for later removing the callback.

Source/Core/InputCommon/ControllerInterface/ControllerInterface.h

@@ -106,6 +106,11 @@ public:
   // Inputs based on window coordinates should be multiplied by this.
   Common::Vec2 GetWindowInputScale() const;
 
+  // Request that the mouse cursor should be centered in the render window at the next opportunity.
+  void SetMouseCenteringRequested(bool center);
+
+  bool IsMouseCenteringRequested() const;
+
   HotplugCallbackHandle RegisterDevicesChangedCallback(std::function<void(void)> callback);
   void UnregisterDevicesChangedCallback(const HotplugCallbackHandle& handle);
   void InvokeDevicesChangedCallbacks() const;
@@ -127,6 +132,7 @@ private:
   std::atomic<int> m_populating_devices_counter;
   WindowSystemInfo m_wsi;
   std::atomic<float> m_aspect_ratio_adjustment = 1;
+  std::atomic<bool> m_requested_mouse_centering = false;
 };
 
 namespace ciface