GitLab

This corrects some deficiencies in the Storage Service's sandboxing
support by eliminating all remaining instances of direct filesystem
traversal within DOM Storage, replacing them with appropriate
FilesystemProxy usage.

A few new IPCs are added to the Directory mojom interface in support of
this, and a new delegate is added to support use of
sql::SandboxedVfs with a FilesystemProxy backing it.

Bug: 1052045
Test: content_browsertests with StorageServiceOutOfProcess and StorageServiceSandbox enabled
Change-Id: I8e7593d9424be705cb3c2bf561a4fe4c5d61251d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2350542
Commit-Queue: Ken Rockot <rockot@google.com>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798710}