Remove MouseWarpController construction from ash::DisplayManager

ash/display/display_manager.h

Index: ash/display/display_manager.h
diff --git a/ash/display/display_manager.h b/ash/display/display_manager.h
index 9730b3a2117ad9d85a588aef6ccb37c64e563dc8..f865ba9f877dcb35770bfdbedc284881272c21bd 100644
--- a/ash/display/display_manager.h
+++ b/ash/display/display_manager.h
@@ -45,7 +45,6 @@ class Rect;
 
 namespace ash {
 class AcceleratorControllerTest;
-class MouseWarpController;
 class ScreenAsh;
 
 using DisplayInfoList = std::vector<display::ManagedDisplayInfo>;
@@ -328,12 +327,6 @@ class ASH_EXPORT DisplayManager
   // is enabled.
   void CreateMirrorWindowAsyncIfAny();
 
-  // Creates a MouseWarpController for the current display
-  // configuration. |drag_source| is the window where dragging
-  // started, or nullptr otherwise.
-  std::unique_ptr<MouseWarpController> CreateMouseWarpController(
-      aura::Window* drag_source) const;
-
   // Create a screen instance to be used during shutdown.
   void CreateScreenForShutdown() const;