[Dial] Refactor DialRegistry and DeviceDescriptionFetcher so they can be used by MediaSinkService

chrome/browser/extensions/api/dial/dial_api.cc

Index: chrome/browser/extensions/api/dial/dial_api.cc
diff --git a/chrome/browser/extensions/api/dial/dial_api.cc b/chrome/browser/extensions/api/dial/dial_api.cc
index 783992bf2befac1cd57264254d3728ba5dc9f878..7377a10142ae1359010d17e87f4c19c034eb27d5 100644
--- a/chrome/browser/extensions/api/dial/dial_api.cc
+++ b/chrome/browser/extensions/api/dial/dial_api.cc
@@ -230,7 +230,8 @@ void DialFetchDeviceDescriptionFunction::MaybeStartFetch(const GURL& url) {
   }
 
   device_description_fetcher_ = base::MakeUnique<DeviceDescriptionFetcher>(
-      url, Profile::FromBrowserContext(browser_context()),
+      url, Profile::FromBrowserContext(browser_context())->GetRequestContext(),
+      BrowserThread::UI,
       base::BindOnce(&DialFetchDeviceDescriptionFunction::OnFetchComplete,
                      this),
       base::BindOnce(&DialFetchDeviceDescriptionFunction::OnFetchError, this));