views: Split DownloadShelfContextMenuWin out to its own header file.

chrome/browser/ui/views/download/download_item_view.h

Index: chrome/browser/ui/views/download/download_item_view.h
diff --git a/chrome/browser/ui/views/download/download_item_view.h b/chrome/browser/ui/views/download/download_item_view.h
index 295d52d1213ac69a49bb9eb3930bd5a3eb94598c..4fe8f46b6bb25f71b203261309bf73fb9d3b2bed 100644
--- a/chrome/browser/ui/views/download/download_item_view.h
+++ b/chrome/browser/ui/views/download/download_item_view.h
@@ -36,7 +36,7 @@
 class BaseDownloadItemModel;
 class DownloadShelfView;
 class SkBitmap;
-class DownloadShelfContextMenuWin;
+class DownloadShelfContextMenuView;
 
 namespace gfx {
 class Image;
@@ -276,7 +276,7 @@ class DownloadItemView : public views::ButtonListener,
   ScopedRunnableMethodFactory<DownloadItemView> reenable_method_factory_;
 
   // The currently running download context menu.
-  scoped_ptr<DownloadShelfContextMenuWin> context_menu_;
+  scoped_ptr<DownloadShelfContextMenuView> context_menu_;
 
   // If non-NULL, set to true when this object is deleted.
   // (Used when showing the context menu as it runs an inner message loop that