Use IOSImageDataFetcherWrapper

components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h

Index: components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h
diff --git a/components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h b/components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h
index 1649cdf34b24ed11e4512a162869e59bbf1322d0..ad1e9e997e72e28f26d34f27bc25656fc627a628 100644
--- a/components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h
+++ b/components/image_fetcher/ios/ios_image_data_fetcher_wrapper.h
@@ -41,8 +41,8 @@ class IOSImageDataFetcherWrapper {
   // http response header is not HTTP_OK (200). If the url is a data URL, the
   // http response header is considered to be HTTP_OK.
   // |callback| cannot be nil.
-  void FetchImageDataWebpDecoded(const GURL& image_url,
-                                 IOSImageDataFetcherCallback callback);
+  virtual void FetchImageDataWebpDecoded(const GURL& image_url,
+                                         IOSImageDataFetcherCallback callback);
 
   // Sets a service name against which to track data usage.
   void SetDataUseServiceName(DataUseServiceName data_use_service_name);