WebUsb Android chooser UI

chrome/browser/usb/web_usb_histograms.h

+// Copyright 2016 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.
+
+#ifndef CHROME_BROWSER_USB_WEB_USB_HISTOGRAMS_H_
+#define CHROME_BROWSER_USB_WEB_USB_HISTOGRAMS_H_
+
+// Reasons the chooser may be closed. These are used in histograms so do not
+// remove/reorder entries. Only add at the end just before
+// WEBUSB_CHOOSER_CLOSED_MAX. Also remember to update the enum listing in
+// tools/metrics/histograms/histograms.xml.
+enum WebUsbChooserClosed {
+  // The user cancelled the permission prompt without selecting a device.
+  WEBUSB_CHOOSER_CLOSED_CANCELLED = 0,
+  // The user probably cancelled the permission prompt without selecting a
+  // device because there were no devices to select.
+  WEBUSB_CHOOSER_CLOSED_CANCELLED_NO_DEVICES,
+  // The user granted permission to access a device.
+  WEBUSB_CHOOSER_CLOSED_PERMISSION_GRANTED,
+  // The user granted permission to access a device but that permission will be
+  // revoked when the device is disconnected.
+  WEBUSB_CHOOSER_CLOSED_EPHEMERAL_PERMISSION_GRANTED,
+  // Maximum value for the enum.
+  WEBUSB_CHOOSER_CLOSED_MAX
+};
+
+void RecordWebUsbChooserClosure(WebUsbChooserClosed disposition);
+
+#endif  // CHROME_BROWSER_USB_WEB_USB_HISTOGRAMS_H_