Add override specifier and member constness to RecoveryUI classes.

Test: mmma bootable/recovery
Change-Id: I66e328614423488a4027d7878f4569fbf3a3721e
diff --git a/wear_ui.cpp b/wear_ui.cpp
index adc316d..640f04a 100644
--- a/wear_ui.cpp
+++ b/wear_ui.cpp
@@ -61,7 +61,7 @@
   self = this;
 }
 
-int WearRecoveryUI::GetProgressBaseline() {
+int WearRecoveryUI::GetProgressBaseline() const {
   return progress_bar_y;
 }