File API: Remove //storage/common/fileapi/file_system_type_converters.h.

The file was deleted for two reasons.

1) Both the File API and the File System API were Onion Souped, so they
   should not have any code shared between the browser and the renderer.
2) Mojo TypeConverters are deprecated and banned in new code.

The dependencies on this code are listed below, together with the steps
taken to remove them.

1) //content/renderer/pepper - fixed by having the renderer-side code
   use blink::mojo::FileSystemType directly, instead of
   storage::FileSystemType. This was accomplished by forking the
   conversion code in //content/common/pepper/pepper_file_util.{cc,h}
   into browser-specific and renderer-specific copies.
2) //content/browser/fileapi - fixed by moving the conversion code to
   the only file using it

Tbr: kinuko
Bug: 992739
Change-Id: I17f5f594b8211fef8a7eb0cf56730fa58bf7569a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1747853
Reviewed-by: Victor Costan <pwnall@chromium.org>
Reviewed-by: Staphany Park <staphany@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685906}
7 files changed