Delete ash-based code for Windows drag-and-drop graphics.

ui/aura/mus/os_exchange_data_provider_mus.cc

Index: ui/aura/mus/os_exchange_data_provider_mus.cc
diff --git a/ui/aura/mus/os_exchange_data_provider_mus.cc b/ui/aura/mus/os_exchange_data_provider_mus.cc
index 538cbb155cc5ca32ce7f345fdb4a179b3f9e1ec9..04e7539f04aeef9e54081120252e31732f89db31 100644
--- a/ui/aura/mus/os_exchange_data_provider_mus.cc
+++ b/ui/aura/mus/os_exchange_data_provider_mus.cc
@@ -325,11 +325,11 @@ void OSExchangeDataProviderMus::SetDragImage(
   drag_image_offset_ = cursor_offset;
 }
 
-const gfx::ImageSkia& OSExchangeDataProviderMus::GetDragImage() const {
+gfx::ImageSkia OSExchangeDataProviderMus::GetDragImage() const {
   return drag_image_;
 }
 
-const gfx::Vector2d& OSExchangeDataProviderMus::GetDragImageOffset() const {
+gfx::Vector2d OSExchangeDataProviderMus::GetDragImageOffset() const {
   return drag_image_offset_;
 }
 #endif