[fsp] Do not crash on an invalid modification time.
Before, if a modification time was InvalidDate, then it caused a crash on
a DCHECK converting a string date to base::Time.
Providers may return an incorrect date, and we shouldn't crash. This patch
resolves this issue by removing the DCHECK and passing the invalid date
to fileapi.
TEST=unit_test: *FileSystemProvider*GetMetadata*
BUG=248427
Review URL: https://codereview.chromium.org/295933002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271959 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed
