Show Submitted Date in change summary

* introduce time format: Yesterday at 16:13
* under feature flag

Change-Id: Ie6d51819b72af8e0fb70cb482b8f0c5e9a6978fd
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
index 88f7351..16b2582 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
@@ -116,6 +116,22 @@
         >
       </div>
     </template>
+    <template is="dom-if" if="[[_isNewChangeSummaryUiEnabled]]">
+      <template is="dom-if" if="[[change.submitted]]">
+        <section
+          class$="[[_computeDisplayState(_showAllSections, change, _SECTION.SUBMITTED)]]"
+        >
+          <span class="title">Submitted</span>
+          <span class="value">
+            <gr-date-formatter
+              has-tooltip=""
+              date-str="[[change.submitted]]"
+              show-yesterday=""
+            ></gr-date-formatter>
+          </span>
+        </section>
+      </template>
+    </template>
     <section
       class$="[[_computeDisplayState(_showAllSections, change, _SECTION.UPDATED)]]"
     >
@@ -124,6 +140,7 @@
         <gr-date-formatter
           has-tooltip=""
           date-str="[[change.updated]]"
+          show-yesterday=""
         ></gr-date-formatter>
       </span>
     </section>
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts
index c64dc2a..05e9a73 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.ts
@@ -30,6 +30,7 @@
   isWithinHalfYear,
   formatDate,
   utcOffsetString,
+  wasYesterday,
 } from '../../../utils/date-util';
 import {TimeFormat, DateFormat} from '../../../constants/constants';
 import {assertNever} from '../../../utils/common-util';
@@ -104,6 +105,9 @@
   @property({type: Boolean})
   hasTooltip = false;
 
+  @property({type: Boolean})
+  showYesterday = false;
+
   /**
    * The title to be used as the native tooltip or by the tooltip behavior.
    */
@@ -222,7 +226,8 @@
     timeFormat?: string,
     dateFormat?: DateFormatPair,
     relative?: boolean,
-    showDateAndTime?: boolean
+    showDateAndTime?: boolean,
+    showYesterday?: boolean
   ) {
     if (!dateStr || !timeFormat || !dateFormat) {
       return '';
@@ -238,6 +243,8 @@
     let format = dateFormat.full;
     if (isWithinDay(now, date)) {
       format = timeFormat;
+    } else if (showYesterday && wasYesterday(now, date)) {
+      return `Yesterday at ${formatDate(date, timeFormat)}`;
     } else {
       if (isWithinHalfYear(now, date)) {
         format = dateFormat.short;
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts
index a5dd6d0..a08a77d 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_html.ts
@@ -25,7 +25,7 @@
   </style>
   <span>
     [[_computeDateStr(dateStr, _timeFormat, _dateFormat, _relative,
-    showDateAndTime)]]
+    showDateAndTime, showYesterday)]]
   </span>
   <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
 `;
diff --git a/polygerrit-ui/app/utils/date-util.ts b/polygerrit-ui/app/utils/date-util.ts
index 1dd2d2f..5101d11 100644
--- a/polygerrit-ui/app/utils/date-util.ts
+++ b/polygerrit-ui/app/utils/date-util.ts
@@ -69,6 +69,16 @@
   return diff < Duration.DAY && date.getDay() === now.getDay();
 }
 
+export function wasYesterday(now: Date, date: Date) {
+  const diff = now.valueOf() - date.valueOf();
+  // return true if date is withing 24 hours and not on the same day
+  if (diff < Duration.DAY && date.getDay() !== now.getDay()) return true;
+
+  // move now to yesterday
+  now.setDate(now.getDate() - 1);
+  return isWithinDay(now, date);
+}
+
 /**
  * Returns true if date is from one to six months.
  */
diff --git a/polygerrit-ui/app/utils/date-util_test.js b/polygerrit-ui/app/utils/date-util_test.js
index a003c65..76d8516 100644
--- a/polygerrit-ui/app/utils/date-util_test.js
+++ b/polygerrit-ui/app/utils/date-util_test.js
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 import '../test/common-test-setup-karma.js';
-import {isValidDate, parseDate, fromNow, isWithinDay, isWithinHalfYear, formatDate} from './date-util.js';
+import {isValidDate, parseDate, fromNow, isWithinDay, isWithinHalfYear, formatDate, wasYesterday} from './date-util.js';
 
 suite('date-util tests', () => {
   suite('parseDate', () => {
@@ -64,6 +64,21 @@
     });
   });
 
+  suite('wasYesterday', () => {
+    test('less 24 hours', () => {
+      assert.isFalse(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 08 2020 02:00:00')));
+      assert.isTrue(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 07 2020 12:00:00')));
+    });
+    test('more 24 hours', () => {
+      assert.isTrue(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 07 2020 2:00:00')));
+      assert.isFalse(wasYesterday(new Date('May 08 2020 12:00:00'),
+          new Date('May 06 2020 14:00:00')));
+    });
+  });
+
   suite('isWithinHalfYear', () => {
     test('basics works', () => {
       assert.isTrue(isWithinHalfYear(new Date('May 08 2020 12:00:00'),