chrome://media-app: Do a case-insensitive comparison for matching media extensions.

Currently this only applies to .mkv files. Without the fix, '.MKV' in
the same folder as a photo won't be navigation options when Backlight
opens. (An .MKV will still be opened if selected by itself.)

Bug: b/169360871
Change-Id: I18cebbdadaa76466860784ab47230c75bfe0660b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2428513Reviewed-by: Rachel Carpenter <carpenterr@chromium.org>
Commit-Queue: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810447}

chromeos/components/media_app_ui/resources/js/launch.js

@@ -599,7 +599,8 @@ async function getFileFromHandle(fileSystemHandle) {
 function isVideoOrImage(file) {
   // Check for .mkv explicitly because it is not a web-supported type, but is in
   // common use on ChromeOS.
-  return /^(image)|(video)\//.test(file.type) || /\.mkv$/.test(file.name);
+  return /^(image)|(video)\//.test(file.type) ||
+      /\.mkv$/.test(file.name.toLowerCase());
 }
 
 /**

chromeos/components/media_app_ui/test/media_app_ui_browsertest.js

@@ -1036,26 +1036,27 @@ TEST_F('MediaAppUIBrowserTest', 'RelatedFiles', async () => {
     {name: 'jiff.gif', type: 'image/gif'},
     {name: 'matroska.emkv'},
     {name: 'matroska.mkv'},
+    {name: 'matryoshka.MKV'},
     {name: 'noext', type: ''},
     {name: 'other.txt', type: 'text/plain'},
     {name: 'text.txt', type: 'text/plain'},
     {name: 'world.webm', type: 'video/webm'},
   ];
   const directory = await createMockTestDirectory(testFiles);
-  const [html, jpg, gif, emkv, mkv, ext, other, txt, webm] =
+  const [html, jpg, gif, emkv, mkv, MKV, ext, other, txt, webm] =
       directory.getFilesSync();
 
   await loadFilesWithoutSendingToGuest(directory, mkv);
-  assertFilesToBe([mkv, webm, jpg, gif], 'mkv');
+  assertFilesToBe([mkv, MKV, webm, jpg, gif], 'mkv');
 
   await loadFilesWithoutSendingToGuest(directory, jpg);
-  assertFilesToBe([jpg, gif, mkv, webm], 'jpg');
+  assertFilesToBe([jpg, gif, mkv, MKV, webm], 'jpg');
 
   await loadFilesWithoutSendingToGuest(directory, gif);
-  assertFilesToBe([gif, mkv, webm, jpg], 'gif');
+  assertFilesToBe([gif, mkv, MKV, webm, jpg], 'gif');
 
   await loadFilesWithoutSendingToGuest(directory, webm);
-  assertFilesToBe([webm, jpg, gif, mkv], 'webm');
+  assertFilesToBe([webm, jpg, gif, mkv, MKV], 'webm');
 
   await loadFilesWithoutSendingToGuest(directory, txt);
   assertFilesToBe([txt, other], 'txt');