[HID] Now HID extends directly PluggableUSBListNode

This avoid duplicate instatiation of callback and save a
considerable amount of flash.

Author: cmaglie

hardware/arduino/avr/libraries/HID/HID.cpp

@@ -36,6 +36,8 @@ HIDDescriptor _hidInterface;
 static HIDDescriptorListNode* rootNode = NULL;
 static uint16_t sizeof_hidReportDescriptor = 0;
 static uint8_t modules_count = 0;
+static uint8_t epType[] = { EP_TYPE_INTERRUPT_IN };
+
 //================================================================================
 //================================================================================
 //	Driver
@@ -132,18 +134,14 @@ bool HID_Setup(USBSetup& setup, uint8_t i)
 
 HID_::HID_(void)
 {
-	static uint8_t endpointType[1];
-	endpointType[0] = EP_TYPE_INTERRUPT_IN;
-
-	static PUSBListNode node;
-	node.setup = &HID_Setup,
-	node.getInterface = &HID_GetInterface,
-	node.getDescriptor = &HID_GetDescriptor,
-	node.numEndpoints = 1,
-	node.numInterfaces = 1,
-	node.endpointType = endpointType,
-
-	HID_ENDPOINT_INT = PluggableUSB.addFunction(&node, &HID_INTERFACE);
+	setup = &HID_Setup;
+	getInterface = &HID_GetInterface;
+	getDescriptor = &HID_GetDescriptor;
+	numEndpoints = 1;
+	numInterfaces = 1;
+	endpointType = epType;
+
+	HID_ENDPOINT_INT = PluggableUSB.addFunction(this, &HID_INTERFACE);
 }
 
 int HID_::begin(void)

hardware/arduino/avr/libraries/HID/HID.h

@@ -24,6 +24,7 @@
 
 #include <stdint.h>
 #include <Arduino.h>
+#include "PluggableUSB.h"
 
 #if defined(USBCON)
 
@@ -53,7 +54,7 @@ class HIDDescriptorListNode {
   uint16_t length;
 };
 
-class HID_
+class HID_ : public PUSBListNode
 {
 public:
   HID_(void);