While screencasting a tab, do not disable rendering updates while hidden.

chrome/browser/ui/gtk/tabs/dragged_tab_controller_gtk.cc

Index: chrome/browser/ui/gtk/tabs/dragged_tab_controller_gtk.cc
diff --git a/chrome/browser/ui/gtk/tabs/dragged_tab_controller_gtk.cc b/chrome/browser/ui/gtk/tabs/dragged_tab_controller_gtk.cc
index a8e957bbe595821395ab870f54723e61b5583403..fa697d1ebce937e6100f9e6d693fe46abc6bc67d 100644
--- a/chrome/browser/ui/gtk/tabs/dragged_tab_controller_gtk.cc
+++ b/chrome/browser/ui/gtk/tabs/dragged_tab_controller_gtk.cc
@@ -435,9 +435,6 @@ void DraggedTabControllerGtk::Attach(TabStripGtk* attached_tabstrip,
       drag_data_->get(i)->original_delegate_ = NULL;
     }
 
-    // Return the WebContents to normalcy.
-    drag_data_->GetSourceWebContents()->SetCapturingContents(false);
-
     // We need to ask the tabstrip we're attached to ensure that the ideal
     // bounds for all its tabs are correctly generated, because the calculation
     // in GetInsertionIndexForDraggedBounds needs them to be to figure out the