Make the id used in IconMsg_DownloadFavicon unique

chrome/browser/favicon/favicon_handler_unittest.cc

Index: chrome/browser/favicon/favicon_handler_unittest.cc
diff --git a/chrome/browser/favicon/favicon_handler_unittest.cc b/chrome/browser/favicon/favicon_handler_unittest.cc
index bdfdcbb4d7a2147f95bd9c46b83bdb5ac0a7b51a..43eb49f3371359b4a4b65fc6105bebb7dca447c4 100644
--- a/chrome/browser/favicon/favicon_handler_unittest.cc
+++ b/chrome/browser/favicon/favicon_handler_unittest.cc
@@ -152,9 +152,10 @@ class TestFaviconHandlerDelegate : public FaviconHandlerDelegate {
     return NULL;
   }
 
-  virtual void StartDownload(int id, const GURL& url, int image_size) {
+  virtual int StartDownload(const GURL& url, int image_size) {
     ADD_FAILURE() << "TestFaviconHandlerDelegate::StartDownload() "
                   << "should never be called in tests.";
+    return -1;
   }
 
   virtual void NotifyFaviconUpdated() {