Add drive::FileSystem::GetFileByPathForSaving().

Add drive::FileSystem::GetFileByPathForSaving().

This is a part of the effort to enable Drive in the Save-As dialog of
Chrome OS for every call site. For that, we need to care about existing
callers that just simply write to local file paths returned by the dialog.

By calling the newly added method, Drive file system will return a local
cache whose modification is monitored for syncing.

BUG=140425
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=216377

[kinaba, 2013-08-07 10:04:15]

It will be used like: https://codereview.chromium.org/22523003/.

[hashimoto, 2013-08-07 10:31:54]

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/file_system.cc (right):

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system.cc:227: file_write_watcher_.reset(new
internal::FileWriteWatcher(observer));
What is this watcher serving for?

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation.h
(right):

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation.h:9:
#include "base/memory/ref_counted.h"
nit: no need to include this?

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation.h:50: //
watched and is automatically uploaded to the server. If the entry is not
nit: "uploaded to the server" Considering what this class exactly does,
something like "notified to the observer" might be better?

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
File
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc
(right):

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc:68:
TestObserver observer;
nit: '_' missing at the end of member variables' names?

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc:88:
EXPECT_EQ(FILE_ERROR_OK, error);
nit: ASSERT_TRUE(entry)?

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc:107:
run_loop.Run();
Don't we need to check the state of the observer?

[kinaba, 2013-08-07 11:28:38]

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/file_system.cc (right):

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system.cc:227: file_write_watcher_.reset(new
internal::FileWriteWatcher(observer));
On 2013/08/07 10:31:54, hashimoto wrote:
> What is this watcher serving for?

Oops. I forgot to remove this prototype impl of mine.

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
File chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation.h
(right):

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation.h:9:
#include "base/memory/ref_counted.h"
On 2013/08/07 10:31:54, hashimoto wrote:
> nit: no need to include this?

Done.

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation.h:50: //
watched and is automatically uploaded to the server. If the entry is not
On 2013/08/07 10:31:54, hashimoto wrote:
> nit: "uploaded to the server" Considering what this class exactly does,
> something like "notified to the observer" might be better?

Done.

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
File
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc
(right):

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc:68:
TestObserver observer;
On 2013/08/07 10:31:54, hashimoto wrote:
> nit: '_' missing at the end of member variables' names?

Done.

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc:88:
EXPECT_EQ(FILE_ERROR_OK, error);
On 2013/08/07 10:31:54, hashimoto wrote:
> nit: ASSERT_TRUE(entry)?

Done.

https://codereview.chromium.org/22335004/diff/1/chrome/browser/chromeos/drive...
chrome/browser/chromeos/drive/file_system/get_file_for_saving_operation_unittest.cc:107:
run_loop.Run();
On 2013/08/07 10:31:54, hashimoto wrote:
> Don't we need to check the state of the observer?

We have to. Done.

[hashimoto, 2013-08-08 06:36:52]

lgtm

[commit-bot: I haz the power, 2013-08-08 10:35:30]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kinaba@chromium.org/22335004/24001

[commit-bot: I haz the power, 2013-08-08 11:20:01]

Change committed as 216377