Adding tests for USB extension API

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

Index: chrome/browser/extensions/api/usb/usb_api.h
diff --git a/chrome/browser/extensions/api/usb/usb_api.h b/chrome/browser/extensions/api/usb/usb_api.h
index 9b46bd32bc93ae37a5e1f36b6d8f2e344beeb95c..93f6b3711bbf29497de343a4cf641ad29742a2c5 100644
--- a/chrome/browser/extensions/api/usb/usb_api.h
+++ b/chrome/browser/extensions/api/usb/usb_api.h
@@ -11,6 +11,8 @@
 #include "chrome/browser/extensions/api/api_resource_manager.h"
 #include "chrome/common/extensions/api/experimental_usb.h"
 
+class UsbDevice;
+
 namespace extensions {
 
 class ApiResourceEventNotifier;
@@ -34,6 +36,8 @@ class UsbFindDeviceFunction : public UsbAsyncApiFunction {
 
   UsbFindDeviceFunction();
 
+  static void SetDeviceForTest(UsbDevice* device);
+
  protected:
   virtual ~UsbFindDeviceFunction();
   virtual bool Prepare() OVERRIDE;
@@ -41,6 +45,8 @@ class UsbFindDeviceFunction : public UsbAsyncApiFunction {
   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_;
 };