[fsp] Add FileSystemURLParser to the file system provider.

[fsp] Add FileSystemURLParser to the file system provider.

The FileSystemURLParser is a class which parses a cracked FileSystemURL to
associate it with the proper ProvidedFileSystem class handling this URL.

This will be necessary to route operations from AsyncFileUtil to a proper
providing extension.

Along the way, the Service class has been fixed. Now, the provided file systems
are gracefully unmounted in destructor. As a result, the external mount points
are cleared neatly.

TEST=unit_tests: FileSystemProviderMountPathUtilTest*
BUG=248427
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=264780

[mtomasz, 2014-04-17 06:28:49]

@kinaba: PTAL. Thanks!

[kinaba, 2014-04-18 05:51:30]

lgtm with a nit

https://codereview.chromium.org/237583015/diff/20001/chrome/browser/chromeos/...
File chrome/browser/chromeos/file_system_provider/service.cc (right):

https://codereview.chromium.org/237583015/diff/20001/chrome/browser/chromeos/...
chrome/browser/chromeos/file_system_provider/service.cc:188:
mount_point_name_to_id_map_.erase(mapping_it);
Simply
mount_point_name_to_id_map_.erase(mount_point_name);

[mtomasz, 2014-04-18 06:56:00]

https://codereview.chromium.org/237583015/diff/20001/chrome/browser/chromeos/...
File chrome/browser/chromeos/file_system_provider/service.cc (right):

https://codereview.chromium.org/237583015/diff/20001/chrome/browser/chromeos/...
chrome/browser/chromeos/file_system_provider/service.cc:188:
mount_point_name_to_id_map_.erase(mapping_it);
On 2014/04/18 05:51:30, kinaba wrote:
> Simply
> mount_point_name_to_id_map_.erase(mount_point_name);

Done.

[mtomasz, 2014-04-18 06:56:05]

The CQ bit was checked by mtomasz@chromium.org

[commit-bot: I haz the power, 2014-04-18 06:56:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mtomasz@chromium.org/237583015/40001

[commit-bot: I haz the power, 2014-04-18 13:02:00]

Change committed as 264780