screen_ui: Use std::string in DrawTextLine() and siblings.

Test: mmma -j bootable/recovery
Test: Build and boot into recovery image on angler. Check the UI.
Test: Repeat the same test on devices using wearable UI.
Change-Id: I1a67ff4ae8de4d7a8dc66326cf07f95c89e95152
diff --git a/wear_ui.cpp b/wear_ui.cpp
index 118e435..e4473ba 100644
--- a/wear_ui.cpp
+++ b/wear_ui.cpp
@@ -61,13 +61,6 @@
   }
 }
 
-static const char* SWIPE_HELP[] = {
-  "Swipe up/down to move.",
-  "Swipe left/right to select.",
-  "",
-  nullptr,
-};
-
 void WearRecoveryUI::draw_screen_locked() {
   draw_background_locked();
   if (!show_text) {
@@ -76,6 +69,13 @@
     SetColor(TEXT_FILL);
     gr_fill(0, 0, gr_fb_width(), gr_fb_height());
 
+    // clang-format off
+    static std::vector<std::string> SWIPE_HELP = {
+      "Swipe up/down to move.",
+      "Swipe left/right to select.",
+      "",
+    };
+    // clang-format on
     draw_menu_and_text_buffer_locked(SWIPE_HELP);
   }
 }
@@ -99,4 +99,4 @@
     update_screen_locked();
   }
   pthread_mutex_unlock(&updateMutex);
-}
\ No newline at end of file
+}