Add new danger type for uncommon or unknown downloads.

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 c2454492c35d51ea8759f1faa0ca005c232d473f..6edf110b144a7b4e9a3d357840e4c8f630c23f89 100644
--- a/chrome/browser/download/download_item_model.cc
+++ b/chrome/browser/download/download_item_model.cc
@@ -138,6 +138,12 @@ string16 DownloadItemModel::GetWarningText(const gfx::Font& font,
           ui::ElideFilename(download_->GetFileNameToReportUser(),
                             font, base_width));
 
+    case content::DOWNLOAD_DANGER_TYPE_UNCOMMON_CONTENT:
+      return l10n_util::GetStringFUTF16(
+          IDS_PROMPT_UNCOMMON_DOWNLOAD_CONTENT,
+          ui::ElideFilename(download_->GetFileNameToReportUser(),
+                            font, base_width));
+
     case content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS:
     case content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT:
     case content::DOWNLOAD_DANGER_TYPE_MAX:
@@ -164,6 +170,7 @@ bool DownloadItemModel::IsMalicious() {
   switch (download_->GetDangerType()) {
     case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL:
     case content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT:
+    case content::DOWNLOAD_DANGER_TYPE_UNCOMMON_CONTENT:
       return true;
 
     case content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS: