Focus input on cherrypick dialog open

Bug: Issue 7407
Change-Id: Ic87053e63a3a3004cebae8fb5d1a4e76d0f07295
(cherry picked from commit f927042808)

polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.js

@@ -69,6 +69,10 @@
       this.fire('cancel', null, {bubbles: false});
     },
 
+    resetFocus() {
+      this.$.branchInput.focus();
+    },
+
     _getProjectBranchesSuggestions(input) {
       if (input.startsWith('refs/heads/')) {
         input = input.substring('refs/heads/'.length);

polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.html

@@ -34,8 +34,10 @@ limitations under the License.
 <script>
   suite('gr-confirm-cherrypick-dialog tests', () => {
     let element;
+    let sandbox;
 
     setup(() => {
+      sandbox = sinon.sandbox.create();
       stub('gr-rest-api-interface', {
         getProjectBranches(input) {
           if (input.startsWith('test')) {
@@ -55,6 +57,8 @@ limitations under the License.
       element.project = 'test-project';
     });
 
+    teardown(() => { sandbox.restore(); });
+
     test('with merged change', () => {
       element.changeStatus = 'MERGED';
       element.commitMessage = 'message\n';
@@ -93,6 +97,12 @@ limitations under the License.
       });
     });
 
+    test('resetFocus', () => {
+      const focusStub = sandbox.stub(element.$.branchInput, 'focus');
+      element.resetFocus();
+      assert.isTrue(focusStub.called);
+    });
+
     test('_getProjectBranchesSuggestions non-empty', done => {
       element._getProjectBranchesSuggestions('test-branch').then(branches => {
         assert.equal(branches.length, 1);