remove unnecessary code

Author: zarend

src/material/datepicker/month-view.ts

@@ -254,20 +254,11 @@ export class MatMonthView<D> implements AfterContentInit, OnChanges, OnDestroy {
 
   _dateBecomesActive(event: MatCalendarUserEvent<number>) {
     const date = event.value;
-    const selectedYear = this._dateAdapter.getYear(this.activeDate);
-    const selectedMonth = this._dateAdapter.getMonth(this.activeDate);
-    const activeDate = this._dateAdapter.createDate(selectedYear, selectedMonth, date);
-    let rangeStartDate: number | null;
-    let rangeEndDate: number | null;
+    const activeYear = this._dateAdapter.getYear(this.activeDate);
+    const activeMonth = this._dateAdapter.getMonth(this.activeDate);
+    const activeDate = this._dateAdapter.createDate(activeYear, activeMonth, date);
 
-    if (this._activeDate instanceof DateRange) {
-      rangeStartDate = this._getDateInCurrentMonth(this._activeDate.start);
-      rangeEndDate = this._getDateInCurrentMonth(this._activeDate.end);
-    } else {
-      rangeStartDate = rangeEndDate = this._getDateInCurrentMonth(this._activeDate);
-    }
-
-    if (rangeStartDate !== date || rangeEndDate !== date) {
+    if (!this._dateAdapter.sameDate(activeDate, this._activeDate)) {
       this.activeDateChange.emit(activeDate);
     }