downloads: clicking "remove" on chrome://downloads should also hide shelf item.

chrome/browser/download/test_download_shelf.cc

Index: chrome/browser/download/test_download_shelf.cc
diff --git a/chrome/browser/download/test_download_shelf.cc b/chrome/browser/download/test_download_shelf.cc
index 9538b7cdc0a8694ec344ba874c4621da833b02cd..e6cebf724c7242a24e0fb6c1f0243bcd63dcdc70 100644
--- a/chrome/browser/download/test_download_shelf.cc
+++ b/chrome/browser/download/test_download_shelf.cc
@@ -17,6 +17,9 @@ TestDownloadShelf::~TestDownloadShelf() {
     download_manager_->RemoveObserver(this);
 }
 
+void TestDownloadShelf::RemoveDownload(content::DownloadItem* download) {
+}
+
 bool TestDownloadShelf::IsShowing() const {
   return is_showing_;
 }