Explore: Fixes incorrect handling of utc in timeEpic (#18386)

* Fix: Fixes incorrect handling of utc in timeEpic

* Chore: Renames dateTimeFromTimeZone to dateTimeForTimeZone

packages/grafana-data/src/utils/datemath.ts

@@ -1,6 +1,6 @@
 import includes from 'lodash/includes';
 import isDate from 'lodash/isDate';
-import { DateTime, dateTime, toUtc, ISO_8601, isDateTime, DurationUnit } from './moment_wrapper';
+import { DateTime, dateTime, dateTimeForTimeZone, ISO_8601, isDateTime, DurationUnit } from './moment_wrapper';
 import { TimeZone } from '../types';
 
 const units: DurationUnit[] = ['y', 'M', 'w', 'd', 'h', 'm', 's'];
@@ -45,11 +45,7 @@ export function parse(text: string | DateTime | Date, roundUp?: boolean, timezon
     let parseString;
 
     if (text.substring(0, 3) === 'now') {
-      if (timezone === 'utc') {
-        time = toUtc();
-      } else {
-        time = dateTime();
-      }
+      time = dateTimeForTimeZone(timezone);
       mathString = text.substring('now'.length);
     } else {
       index = text.indexOf('||');

packages/grafana-data/src/utils/moment_wrapper.ts

@@ -1,3 +1,4 @@
+import { TimeZone } from '../types/time';
 /* tslint:disable:import-blacklist ban ban-types */
 import moment, { MomentInput, DurationInputArg1 } from 'moment';
 
@@ -96,3 +97,15 @@ export const toDuration = (input?: DurationInput, unit?: DurationUnit): DateTime
 export const dateTime = (input?: DateTimeInput, formatInput?: FormatInput): DateTime => {
   return moment(input as MomentInput, formatInput) as DateTime;
 };
+
+export const dateTimeForTimeZone = (
+  timezone?: TimeZone,
+  input?: DateTimeInput,
+  formatInput?: FormatInput
+): DateTime => {
+  if (timezone === 'utc') {
+    return toUtc(input, formatInput);
+  }
+
+  return dateTime(input, formatInput);
+};