Move device/usb classes from the FILE thread to UI thread.

device/usb/usb_device_handle.h

Index: device/usb/usb_device_handle.h
diff --git a/device/usb/usb_device_handle.h b/device/usb/usb_device_handle.h
index 7098d6809ee8a1eb47845b23432c7e901c9e413b..a4ef90465709d6c26d0748566e61045af7b763eb 100644
--- a/device/usb/usb_device_handle.h
+++ b/device/usb/usb_device_handle.h
@@ -30,6 +30,7 @@ enum UsbTransferStatus {
   USB_TRANSFER_LENGTH_SHORT,
 };
 
+typedef base::Callback<void(bool)> UsbSuccessCallback;

[Ken Rockot(use gerrit already), 2015/04/07 22:09:43]

name nit: Maybe UsbResultCallback? SuccessCallback might imply that it's only
called upon success, despite the signature.

[Reilly Grant (use Gerrit), 2015/04/08 21:39:03]

Done.

 typedef base::Callback<
     void(UsbTransferStatus, scoped_refptr<net::IOBuffer>, size_t)>
     UsbTransferCallback;
@@ -49,20 +50,18 @@ class UsbDeviceHandle : public base::RefCountedThreadSafe<UsbDeviceHandle> {
   // The platform device handle will be closed when UsbDeviceHandle destructs.
   virtual void Close() = 0;
 
-  // Device manipulation operations. These methods are blocking and must be
-  // called on FILE thread.
-  virtual bool SetConfiguration(int configuration_value) = 0;
-  virtual bool ClaimInterface(int interface_number) = 0;
+  // Device manipulation operations.
+  virtual void SetConfiguration(int configuration_value,
+                                const UsbSuccessCallback& callback) = 0;
+  virtual void ClaimInterface(int interface_number,
+                              const UsbSuccessCallback& callback) = 0;
   virtual bool ReleaseInterface(int interface_number) = 0;
-  virtual bool SetInterfaceAlternateSetting(int interface_number,
-                                            int alternate_setting) = 0;
-  virtual bool ResetDevice() = 0;
+  virtual void SetInterfaceAlternateSetting(
+      int interface_number,
+      int alternate_setting,
+      const UsbSuccessCallback& callback) = 0;
+  virtual void ResetDevice(const UsbSuccessCallback& callback) = 0;
 
-  // Gets the string descriptor with the given index from the device, or returns
-  // false. This method is blocking and must be called on the FILE thread.
-  virtual bool GetStringDescriptor(uint8 string_id, base::string16* string) = 0;
-
-  // Async IO. Can be called on any thread.
   virtual void ControlTransfer(UsbEndpointDirection direction,
                                TransferRequestType request_type,
                                TransferRecipient recipient,