When the download folder does not exist, change the download folder to a user's "Downloads"

chrome/browser/download/save_package.h

Index: chrome/browser/download/save_package.h
diff --git a/chrome/browser/download/save_package.h b/chrome/browser/download/save_package.h
index 74f55267f413a098d4aeefbdcf411792123bf614..d7a81516686cf6846b47b7bd3b225072fcad9ea5 100644
--- a/chrome/browser/download/save_package.h
+++ b/chrome/browser/download/save_package.h
@@ -124,6 +124,10 @@ class SavePackage : public base::RefCountedThreadSafe<SavePackage>,
   int tab_id() const { return tab_id_; }
   int id() const { return unique_id_; }
 
+  // Determines the saved file name based on the information of the
+  // current page, and then starts to download the page. This method
+  // runs in the background and may finish asynchronously after this
+  // method returns.
   void GetSaveInfo();
 
   // Statics -------------------------------------------------------------------
@@ -196,6 +200,7 @@ class SavePackage : public base::RefCountedThreadSafe<SavePackage>,
 
   void CreateDirectoryOnFileThread(const FilePath& website_save_dir,
                                    const FilePath& download_save_dir,
+                                   const FilePath& default_download_dir,
                                    const std::string& mime_type);
   void ContinueGetSaveInfo(const FilePath& suggested_path,
                            bool can_save_as_complete);