Add emoji dropdown to list of shortcuts

Bug: Issue 11799
Change-Id: I704308e12f645f5a30c2abf3ff82ef4c3581281e

polygerrit-ui/app/behaviors/keyboard-shortcut-behavior/keyboard-shortcut-behavior.html

@@ -180,6 +180,7 @@ shortcuts are.
 
     SEARCH: 'SEARCH',
     SEND_REPLY: 'SEND_REPLY',
+    EMOJI_DROPDOWN: 'EMOJI_DROPDOWN',
   };
 
   const _help = new Map();
@@ -292,6 +293,8 @@ shortcuts are.
       'Show/hide selected inline diff');
 
   _describe(Shortcut.SEND_REPLY, ShortcutSection.REPLY_DIALOG, 'Send reply');
+  _describe(Shortcut.EMOJI_DROPDOWN, ShortcutSection.REPLY_DIALOG,
+      'Emoji dropdown');
 
   // Must be declared outside behavior implementation to be accessed inside
   // behavior functions.
@@ -423,6 +426,9 @@ shortcuts are.
     }
 
     describeBinding(binding) {
+      if (binding.length === 1) {
+        return [binding];
+      }
       return binding.split(':')[0].split('+').map(part => {
         switch (part) {
           case 'shift':

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js

@@ -312,6 +312,7 @@
     keyboardShortcuts() {
       return {
         [this.Shortcut.SEND_REPLY]: null, // DOC_ONLY binding
+        [this.Shortcut.EMOJI_DROPDOWN]: null, // DOC_ONLY binding
         [this.Shortcut.REFRESH_CHANGE]: '_handleRefreshChange',
         [this.Shortcut.OPEN_REPLY_DIALOG]: '_handleOpenReplyDialog',
         [this.Shortcut.OPEN_DOWNLOAD_DIALOG]:

polygerrit-ui/app/elements/gr-app-element.js

@@ -170,6 +170,8 @@
     _bindKeyboardShortcuts() {
       this.bindShortcut(this.Shortcut.SEND_REPLY,
           this.DOC_ONLY, 'ctrl+enter', 'meta+enter');
+      this.bindShortcut(this.Shortcut.EMOJI_DROPDOWN,
+          this.DOC_ONLY, ':');
 
       this.bindShortcut(
           this.Shortcut.OPEN_SHORTCUT_HELP_DIALOG, '?');