Add a parameter to FileStreamWriter::CreateForLocalFile to allow creating new files as well as writing to existing files.
See https://codereview.chromium.org/18023022/ for context; this is needed by upcoming IDB Blob support.

Tzik, please do primary review for filesystem; Kinaba, please review as ChromeOS owner.

BUG=108012
R=kinaba,tzik

Review URL: https://codereview.chromium.org/197233008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258120 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed