Don't pass buffers to HidConnection::Read because it knows the size.

device/hid/hid_connection_mac.h

Index: device/hid/hid_connection_mac.h
diff --git a/device/hid/hid_connection_mac.h b/device/hid/hid_connection_mac.h
index 02dde044d66e5d98302443d8bc231f841cb78dd1..ee3372c11d72d192c60099fc1321c71f633f8957 100644
--- a/device/hid/hid_connection_mac.h
+++ b/device/hid/hid_connection_mac.h
@@ -29,19 +29,16 @@ class HidConnectionMac : public HidConnection {
   explicit HidConnectionMac(HidDeviceInfo device_info);
 
   // HidConnection implementation.
-  virtual void PlatformRead(scoped_refptr<net::IOBufferWithSize> buffer,
-                            const IOCallback& callback) OVERRIDE;
-  virtual void PlatformWrite(uint8_t report_id,
-                             scoped_refptr<net::IOBufferWithSize> buffer,
-                             const IOCallback& callback) OVERRIDE;
-  virtual void PlatformGetFeatureReport(
-      uint8_t report_id,
-      scoped_refptr<net::IOBufferWithSize> buffer,
-      const IOCallback& callback) OVERRIDE;
+  virtual void PlatformRead(const ReadCallback& callback) OVERRIDE;
+  virtual void PlatformWrite(scoped_refptr<net::IOBuffer> buffer,
+                             size_t size,
+                             const WriteCallback& callback) OVERRIDE;
+  virtual void PlatformGetFeatureReport(uint8_t report_id,
+                                        const ReadCallback& callback) OVERRIDE;
   virtual void PlatformSendFeatureReport(
-      uint8_t report_id,
-      scoped_refptr<net::IOBufferWithSize> buffer,
-      const IOCallback& callback) OVERRIDE;
+      scoped_refptr<net::IOBuffer> buffer,
+      size_t size,
+      const WriteCallback& callback) OVERRIDE;
 
  private:
   virtual ~HidConnectionMac();
@@ -55,9 +52,9 @@ class HidConnectionMac : public HidConnection {
                                   CFIndex report_length);
 
   void WriteReport(IOHIDReportType type,
-                   uint8_t report_id,
-                   scoped_refptr<net::IOBufferWithSize> buffer,
-                   const IOCallback& callback);
+                   scoped_refptr<net::IOBuffer> buffer,
+                   size_t size,
+                   const WriteCallback& callback);
 
   void Flush();
   void ProcessInputReport(scoped_refptr<net::IOBufferWithSize> buffer);
@@ -65,7 +62,7 @@ class HidConnectionMac : public HidConnection {
 
   base::ScopedCFTypeRef<IOHIDDeviceRef> device_;
   scoped_refptr<base::MessageLoopProxy> message_loop_;
-  scoped_ptr<uint8_t, base::FreeDeleter> inbound_buffer_;
+  scoped_ptr<uint8_t[]> inbound_buffer_;
 
   std::queue<PendingHidReport> pending_reports_;
   std::queue<PendingHidRead> pending_reads_;