Issue #2002414 by theladebug: Rename Views method cache_start() to cacheStart().

core/modules/views/lib/Drupal/views/Plugin/views/cache/CachePluginBase.php

@@ -215,7 +215,7 @@ function post_render(&$output) { }
    *
    * @see drupal_add_html_head()
    */
-  function cache_start() {
+  public function cacheStart() {
     $this->storage['head'] = drupal_add_html_head();
   }
 

core/modules/views/lib/Drupal/views/Plugin/views/cache/None.php

@@ -23,7 +23,7 @@
  */
 class None extends CachePluginBase {
 
-  function cache_start() { /* do nothing */ }
+  public function cacheStart() { /* do nothing */ }
 
   public function summaryTitle() {
     return t('None');

core/modules/views/lib/Drupal/views/ViewExecutable.php

@@ -1242,7 +1242,7 @@ public function render($display_id = NULL) {
     }
     else {
       if ($cache) {
-        $cache->cache_start();
+        $cache->cacheStart();
       }
 
       // Run pre_render for the pager as it might change the result.