[filesapp] Split private getThumbnail API into per-type variants

Split fileManagerPrivate.getThumbnail() into getDriveThumbnail() and
getPdfThumbnail() to allow implementation-specific arguments: PDF
thumbnailer supports size arguments, Drive thumbnailer only supports
crop and, in future, others that may have their own (and different)
argument needs.

For getPdfThumbnail(), pass through size arguments from the image loader
request to the PDF thumbnailer and pull up default values from C++ to
the image loader JS code, to make them usable in other thumbnailers that
take explicit dimension arguments.

Bug: 1049966
Change-Id: Ia17a32028a7fb510c1755c9fa0283f9a37978331
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2434013
Commit-Queue: Alexander Bolodurin <alexbn@google.com>
Reviewed-by: Ben Wells <benwells@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814141}
GitOrigin-RevId: e76e12a5403a318e6fbde7258e43ba2ac316e85f
1 file changed