Extracted UsbDeviceHandle as interface.

extensions/browser/api/usb/usb_apitest.cc

Index: extensions/browser/api/usb/usb_apitest.cc
diff --git a/extensions/browser/api/usb/usb_apitest.cc b/extensions/browser/api/usb/usb_apitest.cc
index 785031768a053688c78cb46d9358eee2b0b74eba..96d00ece88cdd2e407fbc038d3984931eef813df 100644
--- a/extensions/browser/api/usb/usb_apitest.cc
+++ b/extensions/browser/api/usb/usb_apitest.cc
@@ -84,10 +84,21 @@ class MockUsbDeviceHandle : public UsbDeviceHandle {
                     const UsbTransferCallback& callback));
 
   MOCK_METHOD0(ResetDevice, bool());
+  MOCK_METHOD1(ClaimInterface, bool(const int interface_number));
+  MOCK_METHOD1(ReleaseInterface, bool(const int interface_number));
+  MOCK_METHOD2(SetInterfaceAlternateSetting,
+               bool(const int interface_number, const int alternate_setting));
+  MOCK_METHOD1(GetSerial, bool(base::string16* serial));
+
+  virtual scoped_refptr<UsbDevice> GetDevice() const OVERRIDE {
+    return device_;
+  }
 
   void set_device(UsbDevice* device) { device_ = device; }
 
  protected:
+  UsbDevice* device_;
+
   virtual ~MockUsbDeviceHandle() {}
 };