move key processing to RecoveryUI

Move the key for handling keys from ScreenRecoveryUI to RecoveryUI, so
it can be used by devices without screens.  Remove the UIParameters
struct and replace it with some new member variables in
ScreenRecoveryUI.

Change-Id: I4c0e659edcbedc0b9e86ed261ae4dbb3c6097414
diff --git a/recovery.cpp b/recovery.cpp
index d028cc9..a0d96d2 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -61,8 +61,6 @@
 static const char *TEMPORARY_INSTALL_FILE = "/tmp/last_install";
 static const char *SIDELOAD_TEMP_DIR = "/tmp/sideload";
 
-extern UIParameters ui_parameters;    // from ui.c
-
 RecoveryUI* ui = NULL;
 
 /*
@@ -745,7 +743,7 @@
     ui = device->GetUI();
 
     ui->Init();
-    ui->SetBackground(RecoveryUI::INSTALLING);
+    ui->SetBackground(RecoveryUI::NONE);
     load_volume_table();
     get_args(&argc, &argv);