Warn users about potentially unwanted downloads.

chrome/browser/extensions/api/downloads/downloads_api.cc

Index: chrome/browser/extensions/api/downloads/downloads_api.cc
diff --git a/chrome/browser/extensions/api/downloads/downloads_api.cc b/chrome/browser/extensions/api/downloads/downloads_api.cc
index 0ebe8c59d6784b3ae00b31fd908ea2e2d89a0ff4..03d6613c045d3f5ee2b0ca5bed5e65cb6011fa1d 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api.cc
@@ -106,6 +106,7 @@ const char kDangerFile[] = "file";
 const char kDangerKey[] = "danger";
 const char kDangerSafe[] = "safe";
 const char kDangerUncommon[] = "uncommon";
+const char kDangerUnwanted[] = "unwanted";
 const char kDangerAccepted[] = "accepted";
 const char kDangerHost[] = "host";
 const char kDangerUrl[] = "url";
@@ -146,6 +147,7 @@ const char* kDangerStrings[] = {
   kDangerUncommon,
   kDangerAccepted,
   kDangerHost,
+  kDangerUnwanted
 };
 COMPILE_ASSERT(arraysize(kDangerStrings) == content::DOWNLOAD_DANGER_TYPE_MAX,
                download_danger_type_enum_changed);