Generalize content::URLDataSource so that it can be used by the network service.

chrome/browser/thumbnails/thumbnail_list_source.h

Index: chrome/browser/thumbnails/thumbnail_list_source.h
diff --git a/chrome/browser/thumbnails/thumbnail_list_source.h b/chrome/browser/thumbnails/thumbnail_list_source.h
index e6ddb0b1a3c5e4e7a1f216ff6a671c0590863f21..e6eef9c4d9debeb10095ae9e5863240504d27891 100644
--- a/chrome/browser/thumbnails/thumbnail_list_source.h
+++ b/chrome/browser/thumbnails/thumbnail_list_source.h
@@ -42,7 +42,9 @@ class ThumbnailListSource : public content::URLDataSource {
   std::string GetMimeType(const std::string& path) const override;
   scoped_refptr<base::SingleThreadTaskRunner> TaskRunnerForRequestPath(
       const std::string& path) const override;
-  bool ShouldServiceRequest(const net::URLRequest* request) const override;
+  bool ShouldServiceRequest(const GURL& url,
+                            content::ResourceContext* resource_context,
+                            int render_process_id) const override;
   bool ShouldReplaceExistingSource() const override;
 
  private: