Revert "Mojofy FileSystem"

This reverts commit 104d9bf8175d3ec3feb862cee68808c57ce575af.

Reason for revert: Causes crashes, see https://crbug.com/870567,
https://crbug.com/870629, https://crbug.com/870643, https://crbug.com/870682. Based on the stack traces, they're all the same kind of crash, but reverting just to be safe.

Original change's description:
> Mojofy FileSystem
> 
> - Mojofies and removes all messages in file_system_messages.h.
> - Replaces FileAPIMessageFilter with FileSystemDispatcherHost.
> - Adds mojom types for FileSystemInfo and FileSystemType and adds
>   type converters to convert these types to storage::FileSystemInfo
>   and storage FileSystemInfo respectively. The storage types will be
>   replaced with the mojom types in follow up CLs.
> 
> Change-Id: I82aaf9dcb04149880e68238540766f21771d2b21
> Bug: 787281
> Reviewed-on: https://chromium-review.googlesource.com/1125316
> Reviewed-by: Kinuko Yasuda <[email protected]>
> Reviewed-by: Victor Costan <[email protected]>
> Reviewed-by: Joshua Bell <[email protected]>
> Commit-Queue: Adithya Srinivasan <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#580346}

[email protected],[email protected],[email protected],[email protected]

Change-Id: Id955ec9f01f6201e4de92fbdfb400f3f00109496
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 787281
Reviewed-on: https://chromium-review.googlesource.com/1162201
Reviewed-by: Adithya Srinivasan <[email protected]>
Commit-Queue: Adithya Srinivasan <[email protected]>
Cr-Commit-Position: refs/heads/master@{#580529}
31 files changed