Read HID report descriptor from sysfs and request permission on connect.

Read HID report descriptor from sysfs and request permission on connect.

The HID report descriptor can be read from sysfs instead of executing an
ioctl on the device node. This means that on Chrome OS it isn't
necessary to ask the permission broker for access to the device on
enumeration. It can be delayed until the device is opened, as it is for
USB devices. This also resolves a long-standing issue with HID devices
not being enumerated on Chrome OS the first time an enumeration is
requested because of the extra asynchronous step required only on that
platform.

BUG=411899
Committed: https://crrev.com/7832a4ee148a97057188ecb7165f9252185644f0
Cr-Commit-Position: refs/heads/master@{#299228}

[Reilly Grant (use Gerrit), 2014-10-10 16:53:51]

reillyg@chromium.org changed reviewers:
+ yoz@chromium.org

[Yoyo Zhou, 2014-10-10 23:05:24]

LGTM, I'm not really familiar with the Linux internals though.

https://chromiumcodereview.appspot.com/641203003/diff/1/device/hid/hid_servic...
File device/hid/hid_service_linux.cc (right):

https://chromiumcodereview.appspot.com/641203003/diff/1/device/hid/hid_servic...
device/hid/hid_service_linux.cc:8: #include <sys/ioctl.h>
Don't need this anymore?

https://chromiumcodereview.appspot.com/641203003/diff/1/extensions/browser/ap...
File extensions/browser/api/hid/hid_api.cc (right):

https://chromiumcodereview.appspot.com/641203003/diff/1/extensions/browser/ap...
extensions/browser/api/hid/hid_api.cc:155: hid_service_ =
device::DeviceClient::Get()->GetHidService();
This can be inside the ifdef

[Reilly Grant (use Gerrit), 2014-10-11 01:13:16]

The CQ bit was checked by reillyg@chromium.org

[commit-bot: I haz the power, 2014-10-11 01:13:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/641203003/200001

[commit-bot: I haz the power, 2014-10-11 01:53:06]

Committed patchset #2 (id:200001)

[commit-bot: I haz the power, 2014-10-11 01:53:44]

Patchset 2 (id:??) landed as
https://crrev.com/7832a4ee148a97057188ecb7165f9252185644f0
Cr-Commit-Position: refs/heads/master@{#299228}