Update device/usb and its Mojo interface for variable size ISO packets.

extensions/browser/api/usb/usb_api.h

Index: extensions/browser/api/usb/usb_api.h
diff --git a/extensions/browser/api/usb/usb_api.h b/extensions/browser/api/usb/usb_api.h
index 5bea383226e7522492b31e03c45a00b87bc506da..3d1dec1a02db9008264807e52b7e57b2246e8658 100644
--- a/extensions/browser/api/usb/usb_api.h
+++ b/extensions/browser/api/usb/usb_api.h
@@ -245,7 +245,7 @@ class UsbClaimInterfaceFunction : public UsbConnectionFunction {
 
   UsbClaimInterfaceFunction();
 
- protected:
+ private:
   ~UsbClaimInterfaceFunction() override;
 
   // ExtensionFunction:
@@ -334,7 +334,7 @@ class UsbInterruptTransferFunction : public UsbTransferFunction {
   DISALLOW_COPY_AND_ASSIGN(UsbInterruptTransferFunction);
 };
 
-class UsbIsochronousTransferFunction : public UsbTransferFunction {
+class UsbIsochronousTransferFunction : public UsbConnectionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("usb.isochronousTransfer", USB_ISOCHRONOUSTRANSFER)
 
@@ -346,6 +346,10 @@ class UsbIsochronousTransferFunction : public UsbTransferFunction {
   // ExtensionFunction:
   ResponseAction Run() override;
 
+  void OnCompleted(
+      scoped_refptr<net::IOBuffer> data,
+      const std::vector<device::UsbDeviceHandle::IsochronousPacket>& packets);
+
   DISALLOW_COPY_AND_ASSIGN(UsbIsochronousTransferFunction);
 };