Mac: make save/open dialogs operate as tab-modal sheets....

chrome/browser/download/download_request_manager.h

Index: chrome/browser/download/download_request_manager.h
diff --git a/chrome/browser/download/download_request_manager.h b/chrome/browser/download/download_request_manager.h
index f9351c8895bc98d6dae811fd44ca53ee6e60f98b..f60ab18029db58c41c4eea7fd3da638ec5306ff7 100644
--- a/chrome/browser/download/download_request_manager.h
+++ b/chrome/browser/download/download_request_manager.h
@@ -89,10 +89,11 @@ class DownloadRequestManager :
     // may result in invoking Remove on DownloadRequestManager.
     void OnUserGesture();
 
-    // Asks the user if they really want to allow the download.
+    // Asks the user if they really want to allow the download. Returns |false|
+    // on error (|true| otherwise).
     // See description above CanDownloadOnIOThread for details on lifetime of
     // callback.
-    void PromptUserForDownload(TabContents* tab,
+    bool PromptUserForDownload(TabContents* tab,
                                DownloadRequestManager::Callback* callback);
 
     // Are we showing a prompt to the user?