Clean up HID backend and API.

device/hid/hid_connection.h

 // Copyright (c) 2014 The Chromium 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 DEVICE_HID_HID_CONNECTION_H_
 #define DEVICE_HID_HID_CONNECTION_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/thread_checker.h"
 #include "device/hid/hid_device_info.h"
-
-namespace net {
-class IOBuffer;
-}
+#include "net/base/io_buffer.h"
 
 namespace device {
 
 class HidConnection : public base::RefCountedThreadSafe<HidConnection> {
  public:
   typedef base::Callback<void(bool success, size_t size)> IOCallback;
 
-  virtual void Read(scoped_refptr<net::IOBuffer> buffer,
-                    size_t size,
+  virtual void Read(scoped_refptr<net::IOBufferWithSize> buffer,
                     const IOCallback& callback) = 0;
-  virtual void Write(scoped_refptr<net::IOBuffer> buffer,
-                     size_t size,
+  virtual void Write(scoped_refptr<net::IOBufferWithSize> buffer,
                      const IOCallback& callback) = 0;
-  virtual void GetFeatureReport(scoped_refptr<net::IOBuffer> buffer,
-                                size_t size,
+  virtual void GetFeatureReport(scoped_refptr<net::IOBufferWithSize> buffer,
                                 const IOCallback& callback) = 0;
-  virtual void SendFeatureReport(scoped_refptr<net::IOBuffer> buffer,
-                                 size_t size,
+  virtual void SendFeatureReport(scoped_refptr<net::IOBufferWithSize> buffer,
                                  const IOCallback& callback) = 0;
 
   const HidDeviceInfo& device_info() const;
 
  protected:
   friend class base::RefCountedThreadSafe<HidConnection>;
   friend struct HidDeviceInfo;
 
-  HidConnection(HidDeviceInfo device_info);
+  explicit HidConnection(const HidDeviceInfo& device_info);
   virtual ~HidConnection();
 
-  const HidDeviceInfo device_info_;
-
   base::ThreadChecker thread_checker_;

[Mark Mentovai, 2014/02/21 17:48:18]

It feels a little bit dirty that this is protected. If the base class and the
subclasses all needed a thread checker, then I’d say it’s OK, since it wouldn’t
really be an interface between the base and subclasses, it would just be a handy
way to share the thread checker instead of having to keep more than one. Since
the base doesn’t use thread_checker_ at all, though, then I’ll suggest making
this a member of each of the subclasses instead.

[Ken Rockot(use gerrit already), 2014/02/22 01:17:04]

Done. One per subclass now.

 
+ private:
+  const HidDeviceInfo device_info_;
+
   DISALLOW_COPY_AND_ASSIGN(HidConnection);
 };
 
+struct PendingHidReport {
+  PendingHidReport();
+  ~PendingHidReport();
+
+  scoped_refptr<net::IOBufferWithSize> buffer;
+};
+
+struct PendingHidRead {
+  PendingHidRead();
+  ~PendingHidRead();
+
+  scoped_refptr<net::IOBufferWithSize> buffer;
+  HidConnection::IOCallback callback;
+};
+
 }  // namespace device
 
 #endif  // DEVICE_HID_HID_CONNECTION_H_