gtk: Split DownloadShelfContextMenuGtk out to its own header file.

This moves the implementation of DownloadShelfContextMenuGtk from download_item_gtk.cc to download_shelf_context_menu_gtk.*

BUG=28978
TEST=None

[email protected],[email protected],[email protected]

Review URL: http://codereview.chromium.org/7051021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86193 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 865176c1..5a8cbeb 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -2649,6 +2649,8 @@
         'browser/ui/gtk/download/download_in_progress_dialog_gtk.h',
         'browser/ui/gtk/download/download_item_gtk.cc',
         'browser/ui/gtk/download/download_item_gtk.h',
+        'browser/ui/gtk/download/download_shelf_context_menu_gtk.cc',
+        'browser/ui/gtk/download/download_shelf_context_menu_gtk.h',
         'browser/ui/gtk/download/download_shelf_gtk.cc',
         'browser/ui/gtk/download/download_shelf_gtk.h',
         'browser/ui/gtk/download/download_started_animation_gtk.cc',