Feedback window: Announce file size limit on repeated selection.

Instead of hiding attach-error on fileSelect callback, hook onto the click event to clear out attach-error before fileselected callback is called. This will reannounce the alert as needed.

BUG=chromium:1020047
TEST=ChromeVox on ChromeOS. Verify by choosing files over 3mb over and
over.

Change-Id: I2e41d61c1bc226573a4cc1a30f675b5a6693c486
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1936763Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Ian Barkley-Yeung <iby@chromium.org>
Commit-Queue: Joon Ahn <joonbug@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721167}

chrome/browser/resources/feedback/js/feedback.js

@@ -99,7 +99,6 @@ let sysInfoPageOnSysInfoReadyCallback = null;
  * @param {Event} fileSelectedEvent The onChanged event for the file input box.
  */
 function onFileSelected(fileSelectedEvent) {
-  $('attach-error').hidden = true;
   const file = fileSelectedEvent.target.files[0];
   if (!file) {
     // User canceled file selection.
@@ -119,6 +118,14 @@ function onFileSelected(fileSelectedEvent) {
   attachedFileBlob = file.slice();
 }
 
+/**
+ * Called when user opens the file dialog. Hide $('attach-error') before file
+ * dialog is open to prevent a11y bug https://crbug.com/1020047
+ */
+function onOpenFileDialog() {
+  $('attach-error').hidden = true;
+}
+
 /**
  * Clears the file that was attached to the report with the initial request.
  * Instead we will now show the attach file button in case the user wants to
@@ -577,6 +584,7 @@ function initialize() {
 
     // Setup our event handlers.
     $('attach-file').addEventListener('change', onFileSelected);
+    $('attach-file').addEventListener('click', onOpenFileDialog);
     $('send-report-button').onclick = sendReport;
     $('cancel-button').onclick = cancel;
     $('remove-attached-file').onclick = clearAttachedFile;