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

Review URL: https://codereview.chromium.org/641203003

Cr-Commit-Position: refs/heads/master@{#299228}

1 files changed, 8 insertions, 2 deletions

diff --git a/device/hid/hid_service_linux.h b/device/hid/hid_service_linux.h
index 7c61def..765278f 100644
--- a/device/hid/hid_service_linux.h
+++ b/device/hid/hid_service_linux.h
@@ -23,6 +23,12 @@ class HidServiceLinux : public HidService,
  public:
   HidServiceLinux(scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
 
+#if defined(OS_CHROMEOS)
+  virtual void RequestAccess(
+      const HidDeviceId& device_id,
+      const base::Callback<void(bool success)>& callback) override;
+#endif
+
   virtual scoped_refptr<HidConnection> Connect(const HidDeviceId& device_id)
       override;
 
@@ -34,10 +40,10 @@ class HidServiceLinux : public HidService,
   virtual ~HidServiceLinux();
 
   void OnRequestAccessComplete(
-      const std::string& path,
-      scoped_ptr<HidDeviceInfo> device_info,
+      const base::Callback<void(bool success)>& callback,
       bool success);
 
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
 
   base::WeakPtrFactory<HidServiceLinux> weak_factory_;