Add display scaling and rotation shortcuts to keyboard overlay.

chrome/app/chromeos_strings.grdp

Index: chrome/app/chromeos_strings.grdp
diff --git a/chrome/app/chromeos_strings.grdp b/chrome/app/chromeos_strings.grdp
index c242edb8d677334e5672b297c5881bb5735bd9f5..2b34ef8900663f21dcf14c4489c9deae84d08383 100644
--- a/chrome/app/chromeos_strings.grdp
+++ b/chrome/app/chromeos_strings.grdp
@@ -2984,9 +2984,18 @@ Battery full
   <message name="IDS_KEYBOARD_OVERLAY_RESET_ZOOM" desc="The text in the keyboard overlay to explain the shortcut.">
     Reset zoom
   </message>
+  <message name="IDS_KEYBOARD_OVERLAY_ROTATE_SCREEN" desc="The text in the keyboard overlay to explain the shortcut (Rotate the screen).">
+    Rotate screen
+  </message>
   <message name="IDS_KEYBOARD_OVERLAY_SAVE" desc="The text in the keyboard overlay to explain the shortcut (save page as a file).">
     Save
   </message>
+  <message name="IDS_KEYBOARD_OVERLAY_SCALE_DOWN_UI" desc="The text in the keyboard overlay to explain the shortcut (Scale down the UI).">
+    Scale down UI
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_SCALE_UP_UI" desc="The text in the keyboard overlay to explain the shortcut (Scale up the UI).">
+    Scale up UI
+  </message>
   <message name="IDS_KEYBOARD_OVERLAY_SCREENSHOT_REGION" desc="The text in the keyboard overlay to explain the shortcut (take a screenshot of the selected region).">
     Screenshot region
   </message>