cros: Display VKEY Escape with string of Esc in KSV

Majority of the keyboard layouts use "Esc" or "esc" to present
"Escape". This cl adds special handling to display VKEY_ESCAPE
in Keyboard Shortcut Helper (KSV).

Bug: 821841
Test: manually tested.
Change-Id: I3b514325b5cc371c33c64973d0b0e3f9ee9548c6
Reviewed-on: https://chromium-review.googlesource.com/966872Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543857}

ash/components/shortcut_viewer/keyboard_shortcut_viewer_metadata.cc

@@ -63,6 +63,9 @@ base::Optional<base::string16> GetSpecialStringForKeyboardCode(
       msg_id = ui::DeviceUsesKeyboardLayout2() ? IDS_KSV_MODIFIER_LAUNCHER
                                                : IDS_KSV_MODIFIER_SEARCH;
       break;
+    case ui::VKEY_ESCAPE:
+      msg_id = IDS_KSV_KEY_ESCAPE;
+      break;
     case ui::VKEY_SPACE:
       msg_id = IDS_KSV_KEY_SPACE;
       break;

ash/components/shortcut_viewer_strings.grdp

@@ -58,7 +58,10 @@
     Launcher
   </message>
 
-  <!-- Keys with special meaning -->
+  <!-- Keys with special label -->
+  <message name="IDS_KSV_KEY_ESCAPE" desc="Name of [Esc] key. Shouldn't be translated in many languages.">
+    Esc
+  </message>
   <message name="IDS_KSV_KEY_SPACE" desc="Name of [Space] key.">
     Space
   </message>