[REF] stop overriding postProcess function in activity report detail

The function is the same as master except one extra thing that can be done in the function intended for
report-specific preProcess overrides

CRM/Report/Form/Activity.php

@@ -832,24 +832,13 @@ public function buildQuery($applyLimit = TRUE) {
     return $sql;
   }
 
-  public function postProcess() {
-    //reset value of activity_date
+  /**
+   * Override parent to reset value of activity_date.
+   */
+  public function beginPostProcessCommon() {
     if (!empty($this->_resetDateFilter)) {
-      $this->_formValues["activity_date_time_relative"] = NULL;
+      $this->_formValues['activity_date_time_relative'] = NULL;
     }
-
-    $this->beginPostProcess();
-    $sql = $this->buildQuery(TRUE);
-    $this->buildRows($sql, $rows);
-
-    // format result set.
-    $this->formatDisplay($rows);
-
-    // assign variables to templates
-    $this->doTemplateAssignment($rows);
-
-    // do print / pdf / instance stuff if needed
-    $this->endPostProcess($rows);
   }
 
   /**
@@ -860,6 +849,8 @@ public function postProcess() {
    *
    * @param array $rows
    *   Rows generated by SQL, with an array for each row.
+   *
+   * @throws \CRM_Core_Exception
    */
   public function alterDisplay(&$rows) {
     $entryFound = FALSE;