Warn users about potentially unwanted downloads.

chrome/browser/download/download_danger_prompt.cc

Index: chrome/browser/download/download_danger_prompt.cc
diff --git a/chrome/browser/download/download_danger_prompt.cc b/chrome/browser/download/download_danger_prompt.cc
index d75c6cc040c60b343fb0679b3fa7702b1508492f..95ec322adfaf945aacab2dc881e53caabb7ec281 100644
--- a/chrome/browser/download/download_danger_prompt.cc
+++ b/chrome/browser/download/download_danger_prompt.cc
@@ -124,10 +124,18 @@ string16 DownloadDangerPromptImpl::GetMessage() {
       return l10n_util::GetStringFUTF16(
           IDS_PROMPT_UNCOMMON_DOWNLOAD_CONTENT,
           download_->GetFileNameToReportUser().LossyDisplayName());
-    default:
-      NOTREACHED();
-      return string16();
+    case content::DOWNLOAD_DANGER_TYPE_POTENTIALLY_UNWANTED:
+      return l10n_util::GetStringFUTF16(
+          IDS_PROMPT_POTENTIALLY_UNWANTED_DOWNLOAD,
+          download_->GetFileNameToReportUser().LossyDisplayName());
+    case content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS:
+    case content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT:
+    case content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED:
+    case content::DOWNLOAD_DANGER_TYPE_MAX:
+      break;
   }
+  NOTREACHED();
+  return string16();
 }
 
 string16 DownloadDangerPromptImpl::GetAcceptButtonTitle() {