aura: Allow platform to choose how it retrieves ICCProfile.

ui/views/mus/window_tree_host_mus.cc

Index: ui/views/mus/window_tree_host_mus.cc
diff --git a/ui/views/mus/window_tree_host_mus.cc b/ui/views/mus/window_tree_host_mus.cc
index 3629f2f50764a00bfb5ade96d300108e46515b0f..745c1a6c2fdd65a36f17f882c75689f4ded97520 100644
--- a/ui/views/mus/window_tree_host_mus.cc
+++ b/ui/views/mus/window_tree_host_mus.cc
@@ -94,4 +94,9 @@ void WindowTreeHostMus::OnCloseRequest() {
   OnHostCloseRequested();
 }
 
+gfx::ICCProfile WindowTreeHostMus::GetICCProfileForCurrentDisplay() {
+  // TODO: This should read the profile from mus. crbug.com/647510
+  return gfx::ICCProfile();
+}
+
 }  // namespace views