Add missing dependency to KeyboardShortcutMixin

To use the createTitle method, the missing dependency should be there.

Change-Id: Ia0f5a270facb9f94d1672d5137f21418e9487d22
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
index 532097b..ff303e3 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
@@ -44,6 +44,7 @@
 import {DiffViewMode} from '../../../constants/constants';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {fireEvent} from '../../../utils/event-util';
+import {KeyboardShortcutMixin} from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -60,7 +61,7 @@
 }
 
 @customElement('gr-file-list-header')
-export class GrFileListHeader extends PolymerElement {
+export class GrFileListHeader extends KeyboardShortcutMixin(PolymerElement) {
   static get template() {
     return htmlTemplate;
   }
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts
index 69be729..8b9b80c 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_html.ts
@@ -173,6 +173,7 @@
           class="download"
           title="[[createTitle(Shortcut.OPEN_DOWNLOAD_DIALOG,
                 ShortcutSection.ACTIONS)]]"
+          has-tooltip=""
           on-click="_handleDownloadTap"
           >Download</gr-button
         >
@@ -186,6 +187,7 @@
           link=""
           title="[[createTitle(Shortcut.TOGGLE_ALL_INLINE_DIFFS,
                 ShortcutSection.FILE_LIST)]]"
+          has-tooltip=""
           on-click="_expandAllDiffs"
           >Expand All</gr-button
         >
@@ -195,6 +197,7 @@
           on-click="_collapseAllDiffs"
           title="[[createTitle(Shortcut.TOGGLE_ALL_INLINE_DIFFS,
           ShortcutSection.FILE_LIST)]]"
+          has-tooltip=""
           >Collapse All</gr-button
         >
       </template>