Rename "CheckWritable" to "PrepareForWritableApp" to reflect the actual behavior.

Rename "CheckWritable" to "PrepareForWritableApp" to reflect the actual behavior.

The existing implementation in fact does not check whether the file is
writable or not (see below for the detail.)
Since the current behavior itself is fine for the use cases,
this CL renames the relevant functions, and refactors the implementation
so that the intent is clearer.

Existing implementation tries to open a file with CREATE|READ|WRITE flags
and verifies that the result is either FILE_OK or ALREADY_EXISTS.

This _succeeds_ when read-only file already existed at the location
because ALREADY_EXISTS error precedes write failure.
Considering the fact, it is essentially equivalent to open with OPEN_ALWAYS|READ
and comparing the result just against FILE_OK.

BUG=367028
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=274485

[kinaba, 2014-06-02 00:49:03]

@benwells: Reflecting your comments in
https://docs.google.com/a/chromium.org/document/d/17EC3gddwvREtEb1t4pqohbY53y...
I'd like to abandon the previous complex CL 295383010 and
would like to propose this one (basically just renaming functions
to match there actual behavior.) WDYT?

[benwells, 2014-06-02 23:30:31]

lgtm with a couple of nits

https://codereview.chromium.org/306073004/diff/20001/chrome/browser/chromeos/...
File chrome/browser/chromeos/file_manager/filesystem_api_util.h (right):

https://codereview.chromium.org/306073004/diff/20001/chrome/browser/chromeos/...
chrome/browser/chromeos/file_manager/filesystem_api_util.h:43: // Ensures a file
to exist at |path|, i.e., it does nothing if a file is already
Nit: "Ensures a file exists at |path|..."

https://codereview.chromium.org/306073004/diff/20001/chrome/browser/chromeos/...
chrome/browser/chromeos/file_manager/filesystem_api_util.h:46: void
PrepareNonNativeLocalPathFileForWritableApp(
PathFile is weird. Maybe PrepareNonNativeLocalFileForWritableApp.

[kinaba, 2014-06-03 02:29:54]

https://codereview.chromium.org/306073004/diff/20001/chrome/browser/chromeos/...
File chrome/browser/chromeos/file_manager/filesystem_api_util.h (right):

https://codereview.chromium.org/306073004/diff/20001/chrome/browser/chromeos/...
chrome/browser/chromeos/file_manager/filesystem_api_util.h:43: // Ensures a file
to exist at |path|, i.e., it does nothing if a file is already
On 2014/06/02 23:30:31, benwells wrote:
> Nit: "Ensures a file exists at |path|..."

Done.

https://codereview.chromium.org/306073004/diff/20001/chrome/browser/chromeos/...
chrome/browser/chromeos/file_manager/filesystem_api_util.h:46: void
PrepareNonNativeLocalPathFileForWritableApp(
On 2014/06/02 23:30:31, benwells wrote:
> PathFile is weird. Maybe PrepareNonNativeLocalFileForWritableApp.

Done.

[kinaba, 2014-06-03 02:29:58]

The CQ bit was checked by kinaba@chromium.org

[commit-bot: I haz the power, 2014-06-03 02:31:38]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/kinaba@chromium.org/306073004/40001

[commit-bot: I haz the power, 2014-06-03 06:19:44]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_chromium_chromeos_clang_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_chrome...)

[commit-bot: I haz the power, 2014-06-03 12:39:34]

Change committed as 274485