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