recovery: Add wipe system partition option

Change-Id: Id606cef249a7464037443de6265055803c290d82
diff --git a/recovery.cpp b/recovery.cpp
index f6a9e83..61480ac 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -463,6 +463,16 @@
         break;
       }
 
+      case Device::WIPE_SYSTEM: {
+        save_current_log = true;
+        std::function<bool()> confirm_func = [&device]() {
+          return yes_no(device, "Wipe system?", "  THIS CAN NOT BE UNDONE!");
+        };
+        WipeSystem(ui, ui->IsTextVisible() ? confirm_func : nullptr);
+        if (!ui->IsTextVisible()) return Device::NO_ACTION;
+        break;
+      }
+
       case Device::APPLY_ADB_SIDELOAD:
       case Device::APPLY_SDCARD:
       case Device::ENTER_RESCUE: {