Warn users about potentially unwanted downloads.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index c4997ded9956d9f58b4c2b88e193c67983038f0e..a2916c99113cb871563bd733b4bf1b0984688465 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -2890,6 +2890,10 @@ Psst! Incognito mode <ph name="SHORTCUT_KEY">$1<ex>(Ctrl+Shift+N)</ex></ph> may
          desc="Message shown to the user to validate the download when the download content is classified as uncommon by safebrowsing.">
         <ph name="FILE_NAME">$1<ex>bla.exe</ex></ph> is not commonly downloaded and could be dangerous.
       </message>
+      <message name="IDS_PROMPT_POTENTIALLY_UNWANTED_DOWNLOAD"
+         desc="Message shown on the download shelf when the download is known to modify the browser or system settings.">
+        <ph name="FILE_NAME">$1<ex>bla.exe</ex></ph> might modify your browser or system settings.
+      </message>
       <message name="IDS_CONFIRM_KEEP_DANGEROUS_DOWNLOAD_TITLE"
                desc="Title for the confirmation dialog asking whether the user really meant to keep a dangerous download">
         Confirm Download