exo: Fix cursor scaling for 1.25 DSF

ui/display/manager/managed_display_info.h

 // Copyright (c) 2013 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 UI_DISPLAY_MANAGER_MANAGED_DISPLAY_INFO_H_
 #define UI_DISPLAY_MANAGER_MANAGED_DISPLAY_INFO_H_
 
 #include <stdint.h>
 #include <algorithm>
 #include <array>
@@ skipping 209 matching lines @@
   Display::Rotation GetActiveRotation() const;
 
   // Returns the source which set the active rotation for this display.
   Display::RotationSource active_rotation_source() const {
     return active_rotation_source_;
   }
 
   // Returns the rotation set by a given |source|.
   Display::Rotation GetRotation(Display::RotationSource source) const;
 
+  // Returns a measure of density relative to a display with 1.0 DSF. Unlike the
+  // effective DSF, this is independent from the UI scale.
+  float GetDensityRatio() const;
+
   // Returns the ui scale and device scale factor actually used to create
   // display that chrome sees. This can be different from one obtained
   // from dispaly or one specified by a user in following situation.
   // 1) DSF is 2.0f and UI scale is 2.0f. (Returns 1.0f and 1.0f respectiely)
   // 2) A user specified 0.8x on the device that has 1.25 DSF. 1.25 DSF device
   //    uses 1.0f DFS unless 0.8x UI scaling is specified.
   float GetEffectiveDeviceScaleFactor() const;
 
   // Returns the ui scale used for the device scale factor. This
   // return 1.0f if the ui scale and dsf are both set to 2.0.
@@ skipping 154 matching lines @@
   // If you add a new member, you need to update Copy().
 };
 
 // Resets the synthesized display id for testing. This
 // is necessary to avoid overflowing the output index.
 void DISPLAY_MANAGER_EXPORT ResetDisplayIdForTest();
 
 }  // namespace display
 
 #endif  //  UI_DISPLAY_MANAGER_MANAGED_DISPLAY_INFO_H_