aura: Allow platform to choose how it retrieves ICCProfile.

ui/aura/window_tree_host.h

Index: ui/aura/window_tree_host.h
diff --git a/ui/aura/window_tree_host.h b/ui/aura/window_tree_host.h
index 03dcf1b91f1885ddf622d6f6cd69cbad9bd6d098..f31992c9b99272b3ff9f273a8995f5419e5bd662 100644
--- a/ui/aura/window_tree_host.h
+++ b/ui/aura/window_tree_host.h
@@ -18,6 +18,7 @@
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
+class ICCProfile;
 class Insets;
 class Point;
 class Rect;
@@ -214,6 +215,8 @@ class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
   // Hides the WindowTreeHost.
   virtual void HideImpl() = 0;
 
+  virtual gfx::ICCProfile GetICCProfileForCurrentDisplay();
+
   // Overridden from ui::EventSource:
   ui::EventProcessor* GetEventProcessor() override;