Add a stub recovery UI.

This allows recovery to work on devices without screen.
The stub recovery UI does nothing except print to stdout.

Test: write 'recovery\n--wipe_data\n--reason=wipe_data_from_ota\n'
      to misc and boot to recovery on a device without screen.
Bug: 33175036

Change-Id: Icde698aa2e2e29f4b3d0532dfd3c6a939ac2bc63
diff --git a/wear_ui.h b/wear_ui.h
index 9351d41..5ac6f49 100644
--- a/wear_ui.h
+++ b/wear_ui.h
@@ -23,7 +23,7 @@
-    void Init() override;
+    bool Init() override;
     void SetStage(int current, int max) override;
@@ -52,7 +52,7 @@
     int GetProgressBaseline() override;
-    void InitTextParams() override;
+    bool InitTextParams() override;
     void update_progress_locked() override;