Add .desktop file to download_file_types.asciipb

.desktop files act as shortcuts on Linux, allowing arbitrary code
execution. We should send pings for these files.

Bug: 904182
Change-Id: Ibc26141fb180e843e1ffaf3f78717a9109d2fa9a
Reviewed-on: https://chromium-review.googlesource.com/c/1344552
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611272}
void RecordParallelizableContentLength(int64_t content_length) {
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ContentLength.Parallelizable",
                              content_length / 1024, 1, kMaxFileSizeKb, 50);
}

void RecordParallelizableContentLength(int64_t content_length) {
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ContentLength.Parallelizable",
                              content_length / 1024, 1, kMaxFileSizeKb, 50);
}
