Small cleanups for DownloadShelf API.

* Remove unnecessary type aliases
* Rename DoAddDownload() to DoShowDownload() since it's called from
  ShowDownload()
* Make a function const

This also does some other cleanup (e.g. inlining) in affected functions.

Bug: none
Change-Id: I9dbdb8945e8b3da112e7f436a08ce46349a13f45
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2255789
Reviewed-by: Xing Liu <[email protected]>
Commit-Queue: Peter Kasting <[email protected]>
Auto-Submit: Peter Kasting <[email protected]>
Cr-Commit-Position: refs/heads/master@{#780629}
diff --git a/chrome/browser/download/test_download_shelf.cc b/chrome/browser/download/test_download_shelf.cc
index 587a906f..8b8fd52e 100644
--- a/chrome/browser/download/test_download_shelf.cc
+++ b/chrome/browser/download/test_download_shelf.cc
@@ -21,7 +21,8 @@
   return false;
 }
 
-void TestDownloadShelf::DoAddDownload(DownloadUIModelPtr download) {
+void TestDownloadShelf::DoShowDownload(
+    DownloadUIModel::DownloadUIModelPtr download) {
   did_add_download_ = true;
 }
 
@@ -41,6 +42,6 @@
   is_showing_ = true;
 }
 
-base::TimeDelta TestDownloadShelf::GetTransientDownloadShowDelay() {
+base::TimeDelta TestDownloadShelf::GetTransientDownloadShowDelay() const {
   return base::TimeDelta();
 }