Adding tests for USB extension API

chrome/browser/extensions/api/usb/usb_api.h

 // Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_USB_USB_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_USB_USB_API_H_
 
 #include <string>
 
 #include "chrome/browser/extensions/api/api_function.h"
 #include "chrome/browser/extensions/api/api_resource_manager.h"
 #include "chrome/common/extensions/api/experimental_usb.h"
 
+class UsbDevice;
+
 namespace extensions {
 
 class ApiResourceEventNotifier;
 class UsbDeviceResource;
 
 class UsbAsyncApiFunction : public AsyncApiFunction {
  public:
   UsbAsyncApiFunction();
 
  protected:
   virtual ~UsbAsyncApiFunction();
 
   virtual bool PrePrepare() OVERRIDE;
 
   ApiResourceManager<UsbDeviceResource>* manager_;
 };
 
 class UsbFindDeviceFunction : public UsbAsyncApiFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.usb.findDevice");
 
   UsbFindDeviceFunction();
 
+  static void SetDeviceForTest(UsbDevice* device);
+
  protected:
   virtual ~UsbFindDeviceFunction();
   virtual bool Prepare() OVERRIDE;
   virtual void Work() OVERRIDE;
   virtual bool Respond() OVERRIDE;
 
  private:
+  static UsbDevice* device_for_test_;

[asargent_no_longer_on_chrome, 2012/08/14 22:31:06]

nit: can this just be declared/defined in the .cc file as a file-local static or
in an anonymous namespace? 

+
   scoped_ptr<extensions::api::experimental_usb::FindDevice::Params> parameters_;
   ApiResourceEventNotifier* event_notifier_;
 };
 
 class UsbCloseDeviceFunction : public UsbAsyncApiFunction {
  public:
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.usb.closeDevice");
 
   UsbCloseDeviceFunction();
 
@@ skipping 72 matching lines @@
   virtual bool Respond() OVERRIDE;
 
  private:
   scoped_ptr<extensions::api::experimental_usb::IsochronousTransfer::Params>
       parameters_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_USB_USB_API_H_