Remove the enable_themes build flag and define.

chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc

Index: chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
diff --git a/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc b/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
index 25faf41b62bf099e4cd87ec48c84722bbf643301..594e63dd1cd444d231a40745cc8e7c1f74afad29 100644
--- a/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
+++ b/chrome/browser/ui/webui/md_downloads/md_downloads_ui.cc
@@ -148,10 +148,8 @@ MdDownloadsUI::MdDownloadsUI(content::WebUI* web_ui) : WebUIController(web_ui) {
   // Set up the chrome://downloads/ source.
   content::WebUIDataSource* source = CreateDownloadsUIHTMLSource(profile);
   content::WebUIDataSource::Add(profile, source);
-#if defined(ENABLE_THEMES)
   ThemeSource* theme = new ThemeSource(profile);
   content::URLDataSource::Add(profile, theme);
-#endif
 }
 
 // static