Introducing chrome.usb.getDevices/openDevice API

chrome/browser/usb/usb_service.h

Index: chrome/browser/usb/usb_service.h
diff --git a/chrome/browser/usb/usb_service.h b/chrome/browser/usb/usb_service.h
index e89eff9cf85eb33e3892a103853edc64d6ed3b17..e0a93f6acd456137d4ef70ab0fd8e5181721379f 100644
--- a/chrome/browser/usb/usb_service.h
+++ b/chrome/browser/usb/usb_service.h
@@ -45,6 +45,9 @@ class UsbService {
       int interface_id,
       const base::Callback<void(ScopedDeviceVector vector)>& callback);
 
+
+  scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id);
+
   // Get all of the devices attached to the system, inserting them into
   // |devices|. Clears |devices| before use. The result will be sorted by id
   // in increasing order. Must be called on FILE thread.
@@ -86,6 +89,8 @@ class UsbService {
 
   scoped_refptr<UsbContext> context_;
 
+  uint32 next_unique_id_;
+
   // The map from PlatformUsbDevices to UsbDevices.
   typedef std::map<PlatformUsbDevice, scoped_refptr<UsbDevice> > DeviceMap;
   DeviceMap devices_;