Add a logo to the fastbootd screen.

fastbootd looks too much like recovery, even if you're carefully reading
the menu. It's not obvious the device is in a flashing mode, and it's
too tempting to reboot or unplug the device in this state.

As a first step, this patch adds a big red "fastbootd" logo so it's less
obviously in recovery mode.

Bug: 120429730
Test: manual test
Change-Id: I73359f1fdfdc0b1694993f760fe7f35c5713b24e
diff --git a/ui.cpp b/ui.cpp
index 14b5b09..c12a11b 100644
--- a/ui.cpp
+++ b/ui.cpp
@@ -59,6 +59,7 @@
       brightness_file_(BRIGHTNESS_FILE),
       max_brightness_file_(MAX_BRIGHTNESS_FILE),
       touch_screen_allowed_(false),
+      fastbootd_logo_enabled_(false),
       touch_low_threshold_(android::base::GetIntProperty("ro.recovery.ui.touch_low_threshold",
                                                          kDefaultTouchLowThreshold)),
       touch_high_threshold_(android::base::GetIntProperty("ro.recovery.ui.touch_high_threshold",