cashew: reset local counter on plan transition

src/device.h

 // Copyright (c) 2010, 2011 The Chromium OS 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 SRC_DEVICE_H_
 #define SRC_DEVICE_H_
 
 #include <string>
 
 #include <base/basictypes.h>  // NOLINT
@@ skipping 35 matching lines @@
     virtual const std::string& GetCarrier() const = 0;
 
     // get interface name for this device (e.g., "usb0")
     // returns empty string if we don't know
     virtual const std::string& GetInterface() const = 0;
 
     // Service methods
 
     // start a new byte counter from 0
     // there must not be an existing byte counter
-    // |parent_| will receive periodic updates via Service::OnByteCounterUpdate
+    // parent service will receive periodic updates via OnByteCounterUpdate
     // returns true on success and false on failure
     virtual bool StartByteCounter() = 0;
 
     // destroy any existing byte counter
-    // |parent_| will no longer receive updates after this call
+    // parent service will no longer receive updates after this call
     virtual void StopByteCounter() = 0;
 
     // is the byte counter running?
     virtual bool ByteCounterRunning() const = 0;
 
+    // reset byte counter to an arbitrary baseline value
+    // counter will continue to run and increment relative to new baseline
+    // there must be an existing byte counter
+    // parent service must already have received at least one update
+    virtual void ResetByteCounter(uint64 rx_bytes, uint64 tx_bytes) = 0;
+
     // factory
     static Device* NewDevice(Service * const parent,
                              DBus::Connection& connection,  // NOLINT
                              const DBus::Path& path);
 
   private:
     DISALLOW_COPY_AND_ASSIGN(Device);
 };
 
 }  // namespace cashew
 
 #endif  // SRC_DEVICE_H_