Move device opening from DeviceManager to Device.

device/devices_app/usb/public/interfaces/device.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module device.usb;
 
+enum OpenDeviceError {
+  // Opening the device succeeded.
+  OK,
+
+  // The operating system denied access to the device.
+  ACCESS_DENIED,
+};
+
 enum TransferDirection {
   IN,
   OUT,
 };
 
 enum ControlTransferType {
   STANDARD,
   CLASS,
   VENDOR,
   RESERVED
@@ skipping 105 matching lines @@
   // The transfer succeeded, but the device sent more data than was requested.
   // This applies only to inbound transfers.
   BABBLE,
 
   // The transfer succeeded, but the device sent less data than was requested.
   // This applies only to inbound transfers.
   SHORT_PACKET,
 };
 
 interface Device {
-  // Closes the device. Calling this effectively invalidates the Device object.
+  // Retrieve a DeviceInfo struct containing metadata about the device,
+  // including the set of all available device configurations.
+  GetDeviceInfo() => (DeviceInfo? info);
+
+  // Retrieves the device's currently active configuration. May return null if
+  // the device is unconfigured.
+  GetConfiguration() => (ConfigurationInfo? info);
+
+  // Opens the device. Methods below require the device be opened first.
+  Open() => (OpenDeviceError error);
+
+  // Closes the device.
   Close() => ();
 
-  // Retrieve a DeviceInfo struct containing metadata about the device,
-  // including the set of all available device configurations. May return null
-  // if the device has been closed.
-  GetDeviceInfo() => (DeviceInfo? info);
-
   // Initiates a device control transfer to set the device's configuration to
   // one with the configuration value |value|.
   SetConfiguration(uint8 value) => (bool success);
 
   // Claims a single interface in the current device configuration.
   ClaimInterface(uint8 interface_number) => (bool success);
 
   // Releases a claimed interface in the current device configuration.
   ReleaseInterface(uint8 interface_number) => (bool success);
 
@@ skipping 98 matching lines @@
   // this transfer.
   //
   // |timeout| specifies the request timeout in milliseconds. A timeout of 0
   // indicates no timeout: the request will remain pending indefinitely until
   // completed or otherwise terminated.
   IsochronousTransferOut(uint8 endpoint_number,
                          array<array<uint8>> packets,
                          uint32 timeout)
       => (TransferStatus status);
 };