Load Mac download shelf icons asynchronously.

BUG=16226 (http://crbug.com/16226)
TEST=none.

Review URL: http://codereview.chromium.org/155831

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21305 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 16 insertions, 2 deletions

diff --git a/chrome/browser/cocoa/download_item_mac.h b/chrome/browser/cocoa/download_item_mac.h
index 7f31c2a..f992e21 100644
--- a/chrome/browser/cocoa/download_item_mac.h
+++ b/chrome/browser/cocoa/download_item_mac.h
@@ -9,13 +9,16 @@
 
 #include "base/scoped_nsobject.h"
 #include "base/scoped_ptr.h"
+#include "chrome/browser/cancelable_request.h"
 #include "chrome/browser/download/download_manager.h"
+#include "chrome/browser/icon_manager.h"
 
 class BaseDownloadItemModel;
 @class DownloadItemController;
 
-// A class that bridges the visible mac download items to chromium's
-// download model.
+// A class that bridges the visible mac download items to chromium's download
+// model. The owning object (DownloadItemController) must explicitly call
+// |LoadIcon| if it wants to display the icon associated with this download.
 
 class DownloadItemMac : DownloadItem::Observer {
  public:
@@ -32,12 +35,23 @@ class DownloadItemMac : DownloadItem::Observer {
 
   BaseDownloadItemModel* download_model() { return download_model_.get(); }
 
+  // Asynchronous icon loading support.
+  void LoadIcon();
+
  private:
+  // Callback for asynchronous icon loading.
+  void OnExtractIconComplete(IconManager::Handle handle, SkBitmap* icon_bitmap);
+
   // The download item model we represent.
   scoped_ptr<BaseDownloadItemModel> download_model_;
 
   // The objective-c controller object.
   DownloadItemController* item_controller_;  // weak, owns us.
+
+  // For canceling an in progress icon request.
+  CancelableRequestConsumerT<int, 0> icon_consumer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadItemMac);
 };
 
 #endif  // CHROME_BROWSER_COCOA_DOWNLOAD_ITEM_MAC_H_