CCA: Remove thumbnail size limit for video

The size limit optimization only applies for fragemented MP4. Chrome
needs the whole file of a non-fragemented MP4 to be able to play it.

Bug: 1140852
Test: Record a video and check the thumbnail manually.
Change-Id: I3f4d6d7c317c21203761372265b7283bac4734f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2513415
Auto-Submit: Shik Chen <shik@chromium.org>
Commit-Queue: Inker Kuo <inker@chromium.org>
Reviewed-by: Inker Kuo <inker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823394}

chromeos/components/camera_app_ui/resources/js/gallerybutton.js

@@ -21,15 +21,6 @@ import * as util from './util.js';
  */
 const THUMBNAIL_WIDTH = 240;
 
-/**
- * The maximum size of video used to generate the thumbnail. The file would be
- * truncated to that size before generating the thumbnail, which speeds up the
- * generation process significantly when the file is large. 32MB should be more
- * than enough for getting the first frame from a video.
- * @type {number}
- */
-const VIDEO_THUMBNAIL_SIZE_LIMIT = 32 << 20;
-
 /**
  * Cover photo of gallery button.
  */
@@ -74,8 +65,7 @@ class CoverPhoto {
    */
   static async create(file) {
     const isVideo = filesystem.hasVideoPrefix(file);
-    const limit = isVideo ? VIDEO_THUMBNAIL_SIZE_LIMIT : Infinity;
-    const fileUrl = await filesystem.pictureURL(file, {limit});
+    const fileUrl = await filesystem.pictureURL(file);
     const thumbnail =
         await util.scalePicture(fileUrl, isVideo, THUMBNAIL_WIDTH);
     URL.revokeObjectURL(fileUrl);

chromeos/components/camera_app_ui/resources/js/models/file_system.js

@@ -146,16 +146,11 @@ export async function getEntries() {
 }
 
 /**
- * Returns an URL for a picture given by the file |entry|. Optionally, if
- * |limit| is specified, the file would be truncated if it's larger than it.
+ * Returns an URL for a picture given by the file |entry|.
  * @param {!AbstractFileEntry} entry The file entry of the picture.
- * @param {{limit: (number|undefined)}=} options
  * @return {!Promise<string>} Promise for the result.
  */
-export async function pictureURL(entry, {limit = Infinity} = {}) {
-  let file = await entry.file();
-  if (file.size > limit) {
-    file = file.slice(0, limit);
-  }
+export async function pictureURL(entry) {
+  const file = await entry.file();
   return URL.createObjectURL(file);
 }