Coverity: Fix a pass-by-value.

CID_COUNT=1
CID=104610
BUG=none
R=khorimoto@chromium.org
TBR=sky


Review URL: https://chromiumcodereview.appspot.com/10829154

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149765 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/visitedlink/visitedlink_master.cc

@@ -65,7 +65,7 @@ void GenerateSalt(uint8 salt[LINK_SALT_LENGTH]) {
 }
 
 // Opens file on a background thread to not block UI thread.
-void AsyncOpen(FILE** file, FilePath filename) {
+void AsyncOpen(FILE** file, const FilePath& filename) {
   *file = OpenFile(filename, "wb+");
   DLOG_IF(ERROR, !(*file)) << "Failed to open file " << filename.value();
 }