Docserver: Add FileSystem.Exists method and start sanity checking path format

Docserver: Add FileSystem.Exists method and start sanity checking path format
via a new path_utils utility.

BUG=none
R=yoz@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248730

[Yoyo Zhou, 2014-02-04 00:27:19]

LGTM, nits

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
File chrome/common/extensions/docs/server2/file_system.py (right):

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
chrome/common/extensions/docs/server2/file_system.py:85: False is not. This
method will not throw a FileNotFoundError unlike
s/is/if/

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
chrome/common/extensions/docs/server2/file_system.py:133: Behaviour is very
similar to os.walk from the standard os module, yielding
nice spelling =)

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
chrome/common/extensions/docs/server2/file_system.py:135: and |dirs| is relative
to |root|, and |files| and |dirs| are the files and
delete 'is'

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
chrome/common/extensions/docs/server2/file_system.py:136: dirs in |base|
respectively.
Clarify that files and dirs are lists.

[Yoyo Zhou, 2014-02-04 00:30:03]

Oops, reading the next patch:

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
File chrome/common/extensions/docs/server2/file_system.py (right):

https://chromiumcodereview.appspot.com/149513014/diff/1/chrome/common/extensi...
chrome/common/extensions/docs/server2/file_system.py:134: (base, files, dirs)
recursively, where |base| is the base path of |files|
Seems like this is actually base, dirs, files.

[not at google - send to devlin, 2014-02-04 16:14:40]

https://codereview.chromium.org/149513014/diff/1/chrome/common/extensions/doc...
File chrome/common/extensions/docs/server2/file_system.py (right):

https://codereview.chromium.org/149513014/diff/1/chrome/common/extensions/doc...
chrome/common/extensions/docs/server2/file_system.py:85: False is not. This
method will not throw a FileNotFoundError unlike
On 2014/02/04 00:27:20, Yoyo Zhou wrote:
> s/is/if/

Done.

https://codereview.chromium.org/149513014/diff/1/chrome/common/extensions/doc...
chrome/common/extensions/docs/server2/file_system.py:133: Behaviour is very
similar to os.walk from the standard os module, yielding
On 2014/02/04 00:27:20, Yoyo Zhou wrote:
> nice spelling =)

are you referring to my favourite way of spelling behaviour?

https://codereview.chromium.org/149513014/diff/1/chrome/common/extensions/doc...
chrome/common/extensions/docs/server2/file_system.py:134: (base, files, dirs)
recursively, where |base| is the base path of |files|
On 2014/02/04 00:30:03, Yoyo Zhou wrote:
> Seems like this is actually base, dirs, files.

yes. Thank you.

https://codereview.chromium.org/149513014/diff/1/chrome/common/extensions/doc...
chrome/common/extensions/docs/server2/file_system.py:135: and |dirs| is relative
to |root|, and |files| and |dirs| are the files and
On 2014/02/04 00:27:20, Yoyo Zhou wrote:
> delete 'is'

Done.

https://codereview.chromium.org/149513014/diff/1/chrome/common/extensions/doc...
chrome/common/extensions/docs/server2/file_system.py:136: dirs in |base|
respectively.
On 2014/02/04 00:27:20, Yoyo Zhou wrote:
> Clarify that files and dirs are lists.

Done.

[not at google - send to devlin, 2014-02-04 16:24:37]

Committed patchset #3 manually as r248730.