Updating trunk VERSION from 1729.0 to 1730.0

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238899 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238899
Don't revoke SyncFileSystem in SyncFileSystemBackend dtor

Revoking SyncFileSystem globally removes the
'syncfs' mount point, which could cause INVALID_URL error (== EncodingError) on any syncfs URL conversions.

Also added ExternalFileSystem::RevokeAllFileSystems() so that tests like
ChromeOSFileSystemBackendTest.DefaultMountPoints that assumes no
global external mount points are registered before the test runs can use it.

(Ideally we should call RevokeAllFileSystems() at the end of all tests that create
FileSystemContext, but that sounds impractical)

BUG=325588

Review URL: https://codereview.chromium.org/101523004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238901 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238901