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

chrome/browser/download/download_manager.h

Index: chrome/browser/download/download_manager.h
diff --git a/chrome/browser/download/download_manager.h b/chrome/browser/download/download_manager.h
index e072d42498fcd2310388d3f879e2b1c0f4798f8d..4a5814bb62ea33c4bdc98b1dfec2d2222f197eaf 100644
--- a/chrome/browser/download/download_manager.h
+++ b/chrome/browser/download/download_manager.h
@@ -86,7 +86,9 @@ class DownloadManager
     // Called immediately after the DownloadManager puts up a select file
     // dialog.
     // |id| indicates which download opened the dialog.
-    virtual void SelectFileDialogDisplayed(int32 id) {}
+    // |suggested_path| indicates the path suggested in the dialog.
+    virtual void SelectFileDialogDisplayed(
+        int32 id, const FilePath& suggested_path) {}
 
    protected:
     virtual ~Observer() {}
@@ -251,6 +253,17 @@ class DownloadManager
   // For debugging.
   void AssertNotInQueues(DownloadItem* download);
 
+  // Chooses a writable directory from |website_save_dir|, |download_save_dir|
+  // and |default_download_dir| in this order of priority.
+  // If none of them is writable, creates |download_save_dir| and
+  // chooses |download_save_dir|. The choosed directory is stored to |save_dir|.
+  // Returns true if neither |website_save_dir| nor |download_save_dir|
+  // is writable, which indicates the select file dialog should be displayed.
+  static bool ChooseSavableDirectory(const FilePath& website_save_dir,

[Paweł Hajdan Jr., 2011/06/15 09:31:33]

Let's avoid having static methods in DownloadManager. Could you move this to
download_util, or, if Randy doesn't like it, find a different place for it?

[haraken1, 2011/06/15 10:39:45]

Actually, I also prefer download_util.cc to download_manager.cc, although I am
not sure if download_util.cc is the best place. I would like to wait for Randy's
opinion. (No change for now.)

[Randy Smith (Not in Mondays), 2011/06/15 19:48:59]

Pawel: Why do you prefer not to have static methods on DownloadManager?  The
argument I know of against static methods is that they can't be mocked by
inheriting the class--I think that's a valid argument, but if we're comparing
download_util.cc to putting it on DownloadManager, it doesn't apply.  So I
presume there's some argument against static methods I'm missing?  I feel like
DownloadManager is the right place for this functionality...?

[Paweł Hajdan Jr., 2011/06/16 17:41:31]

No, actually I'm fine with static methods per se. However, I'd like to keep any
code that doesn't _have_ to be in DownloadManager out of DownloadManager. The
class is unfortunately named ("Manager"), and there is a tendency to put
anything related to downloads inside it.

[haraken1, 2011/06/22 18:01:58]

Randy:
In conclusion, I placed ChooseSavableDirectory() in download_util.cc.

+                                     const FilePath& download_save_dir,
+                                     const FilePath& default_download_dir,
+                                     FilePath* save_dir);
+
  private:
   // For testing.
   friend class DownloadManagerTest;
@@ -288,7 +301,8 @@ class DownloadManager
   // stalls from interacting with the file system.
   void CheckIfSuggestedPathExists(int32 download_id,
                                   DownloadStateInfo state,
-                                  const FilePath& default_path);
+                                  const FilePath& download_save_dir,
+                                  const FilePath& default_download_dir);
 
   // Called on the UI thread once the DownloadManager has determined whether the
   // suggested file path exists.