Turn on text display for debuggable builds

For userdebug and eng builds, turn on the text display automatically
if no command is specified.

(cherry-pick of 785d22c88cda46972331c04ebc9df97371a696da.)

Bug: http://b/17489952
Change-Id: I38377c45f2a8e45ca788e5506695aa88c769cbcf
diff --git a/recovery.cpp b/recovery.cpp
index 4dd8279..65172df 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -1086,6 +1086,13 @@
     } else if (!just_exit) {
         status = INSTALL_NONE;  // No command specified
         ui->SetBackground(RecoveryUI::NO_COMMAND);
+
+        // http://b/17489952
+        // If this is an eng or userdebug build, automatically turn on the
+        // text display if no command is specified.
+        if (is_ro_debuggable()) {
+            ui->ShowText(true);
+        }
     }
 
     if (!sideload_auto_reboot && (status == INSTALL_ERROR || status == INSTALL_CORRUPT)) {