[network] Correctly reset <input type="file"> upload elements.

This addresses an issue where one cannot upload the same (HAR) file
multiple times in a row, because the underlying HTMLInputElement is
not correctly reset.

Fixed: 346406109
Change-Id: I3050dc1aa4a20e475db604de87d9f3a40faf2938
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6062782
Auto-Submit: Benedikt Meurer <[email protected]>
Commit-Queue: Danil Somsikov <[email protected]>
Commit-Queue: Benedikt Meurer <[email protected]>
Reviewed-by: Danil Somsikov <[email protected]>

Author: bmeurer

front_end/ui/legacy/UIUtils.ts

@@ -1569,11 +1569,14 @@ export function createFileSelectorElement(callback: (arg0: File) => void, accept
   }
   fileSelectorElement.style.display = 'none';
   fileSelectorElement.tabIndex = -1;
-  fileSelectorElement.onchange = () => {
-    if (fileSelectorElement.files) {
+  fileSelectorElement.addEventListener('change', () => {
+    if (fileSelectorElement.files?.length) {
       callback(fileSelectorElement.files[0]);
     }
-  };
+  });
+  fileSelectorElement.addEventListener('click', () => {
+    fileSelectorElement.value = '';
+  });
 
   return fileSelectorElement;
 }