Adds Windows support to the chromium_builder_asan target.

BUG=

Review URL: https://codereview.chromium.org/25492004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226310 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226310
ChildProcessSecurityPolicy: Rationalize PlatformFileFlags used.

Eventually I want to move from PlatformFileFlags to a custom set of flags. Before that, here is an attempted rationalization and unification with the PlatformFileFlags defined in fileapi/file_permission_policy. This is so I have a firm basis to work off of.

Depends on:
https://codereview.chromium.org/24406003/

This is part of Step 4 of this refactoring plan:
https://docs.google.com/a/google.com/document/d/1QGkGWuwgSuaRqovz4wyb0upqPKDVsgYOFKt44E7gmOE/edit?usp=sharing

BUG=262142, 263150

Review URL: https://codereview.chromium.org/24631002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226311 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226311