Remove BrowserThread dependency from usb_service.

components/usb_service/usb_device_handle_impl.h

 // Copyright 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 COMPONENTS_USB_SERVICE_USB_DEVICE_HANDLE_IMPL_H_
 #define COMPONENTS_USB_SERVICE_USB_DEVICE_HANDLE_IMPL_H_
 
 #include <map>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "base/threading/thread_checker.h"
 #include "components/usb_service/usb_device_handle.h"
 #include "components/usb_service/usb_interface.h"
 #include "net/base/io_buffer.h"
-
-struct libusb_device_handle;
-struct libusb_iso_packet_descriptor;
-struct libusb_transfer;
+#include "third_party/libusb/src/libusb/libusb.h"
 
 namespace base {
-class MessageLoopProxy;
+class SingleThreadTaskRunner;
 }
 
 namespace usb_service {
 
 class UsbContext;
 class UsbConfigDescriptor;
 class UsbDeviceImpl;
 
 typedef libusb_device_handle* PlatformUsbDeviceHandle;
 typedef libusb_iso_packet_descriptor* PlatformUsbIsoPacketDescriptor;
@@ skipping 55 matching lines @@
 
   // This constructor is called by UsbDevice.
   UsbDeviceHandleImpl(scoped_refptr<UsbContext> context,
                       UsbDeviceImpl* device,
                       PlatformUsbDeviceHandle handle,
                       scoped_refptr<UsbConfigDescriptor> interfaces);
 
   virtual ~UsbDeviceHandleImpl();
 
  private:
-  friend void HandleTransferCompletion(PlatformUsbTransferHandle handle);
-
   class InterfaceClaimer;
   struct Transfer;
 
   // Refresh endpoint_map_ after ClaimInterface, ReleaseInterface and
   // SetInterfaceAlternateSetting.
   void RefreshEndpointMap();
 
   // Look up the claimed interface by endpoint. Return NULL if the interface
   // of the endpoint is not found.
   scoped_refptr<InterfaceClaimer> GetClaimedInterfaceForEndpoint(
       unsigned char endpoint);
 
+  // If the device's task runner is on the current thread then the transfer will
+  // be submitted directly, otherwise a task to do so it posted. The callback
+  // will be called on the current message loop of the thread where this
+  // function was called.
+  void PostOrSubmitTransfer(PlatformUsbTransferHandle handle,
+                            UsbTransferType transfer_type,
+                            net::IOBuffer* buffer,
+                            size_t length,
+                            const UsbTransferCallback& callback);
+
   // Submits a transfer and starts tracking it. Retains the buffer and copies
   // the completion callback until the transfer finishes, whereupon it invokes
   // the callback then releases the buffer.
   void SubmitTransfer(PlatformUsbTransferHandle handle,
                       UsbTransferType transfer_type,
                       net::IOBuffer* buffer,
                       const size_t length,
-                      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+                      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                       const UsbTransferCallback& callback);
 
+  static void LIBUSB_CALL
+      PlatformTransferCallback(PlatformUsbTransferHandle handle);
+
   // Invokes the callbacks associated with a given transfer, and removes it from
   // the in-flight transfer set.
-  void TransferComplete(PlatformUsbTransferHandle transfer);
+  void CompleteTransfer(PlatformUsbTransferHandle transfer);
 
   bool GetSupportedLanguages();
   bool GetStringDescriptor(uint8 string_id, base::string16* string);
 
   // Informs the object to drop internal references.
   void InternalClose();
 
   UsbDeviceImpl* device_;
 
   PlatformUsbDeviceHandle handle_;
@@ skipping 10 matching lines @@
   TransferMap transfers_;
 
   // A map from endpoints to interfaces
   typedef std::map<int, int> EndpointMap;
   EndpointMap endpoint_map_;
 
   // Retain the UsbContext so that the platform context will not be destroyed
   // before this handle.
   scoped_refptr<UsbContext> context_;
 
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbDeviceHandleImpl);
 };
 
 }  // namespace usb_service
 
 #endif  // COMPONENTS_USB_SERVICE_USB_DEVICE_HANDLE_IMPL_H_