Detect removed files and reflect the state in chrome://downloads and the download shelf

chrome/browser/download/download_item_model.cc

Index: chrome/browser/download/download_item_model.cc
diff --git a/chrome/browser/download/download_item_model.cc b/chrome/browser/download/download_item_model.cc
index 760d13678ed0b44fed95974c7cf314c328441fc8..dd1ab63cc454ce9e02b722c6a3bdd36135fa26c2 100644
--- a/chrome/browser/download/download_item_model.cc
+++ b/chrome/browser/download/download_item_model.cc
@@ -77,7 +77,11 @@ string16 DownloadItemModel::GetStatusText() {
       }
       break;
     case DownloadItem::COMPLETE:
-      status_text.clear();
+      if (download_->file_externally_removed()) {
+        status_text = l10n_util::GetStringUTF16(IDS_DOWNLOAD_STATUS_REMOVED);
+      } else {
+        status_text.clear();
+      }
       break;
     case DownloadItem::CANCELLED:
       status_text = l10n_util::GetStringUTF16(IDS_DOWNLOAD_STATUS_CANCELED);