[Downloads] Prevent dangerous files from being opened automatically.

chrome/browser/download/download_prefs.h

Index: chrome/browser/download/download_prefs.h
diff --git a/chrome/browser/download/download_prefs.h b/chrome/browser/download/download_prefs.h
index e4d82594aa3b474cd1c8bfd2c5a6b5756221b7be..74efc32469f9b48aa1b43778bd39b38f9eb9e40a 100644
--- a/chrome/browser/download/download_prefs.h
+++ b/chrome/browser/download/download_prefs.h
@@ -66,8 +66,8 @@ class DownloadPrefs {
   // |path.Extension()|.
   bool IsAutoOpenEnabledBasedOnExtension(const base::FilePath& path) const;
 
-  // Enables auto-open based on file extension. Returns true on success.
-  // TODO(phajdan.jr): Add WARN_UNUSED_RESULT here.
+  // Enables auto-open based on file extension. Returns true on success. Will
+  // fail if the |file_name| isn't allowed to open automatically.

[Randy Smith (Not in Mondays), 2015/06/15 19:19:17]

I find this on second reading a little confusing.  I read these two sentences as
"Returns true on success.  One way to fail is if the file_name isn't allowed to
open automatically." which from an API contract point of view seems like either
too much or too little documentation.  If we trust the code, the only reason the
function will return false is if the file name isn't allowed to open
automatically; is that worth making clearer?  Or do we want to fuzz the API
contract a bit?

[asanka, 2015/06/16 19:23:42]

Reworded.

   bool EnableAutoOpenBasedOnExtension(const base::FilePath& file_name);
 
   // Disables auto-open based on file extension.