Fix missing backing store in Linux.

chrome/browser/tab_contents/web_contents_view_gtk.cc

Index: chrome/browser/tab_contents/web_contents_view_gtk.cc
diff --git a/chrome/browser/tab_contents/web_contents_view_gtk.cc b/chrome/browser/tab_contents/web_contents_view_gtk.cc
index 809c6c9586b3575fd39906a40f2fcae810bab62a..43fdb80ae10909eb83e6918482e7f030479352f9 100644
--- a/chrome/browser/tab_contents/web_contents_view_gtk.cc
+++ b/chrome/browser/tab_contents/web_contents_view_gtk.cc
@@ -101,7 +101,6 @@ RenderWidgetHostView* WebContentsViewGtk::CreateViewForWidget(
   g_signal_connect(view->native_view(), "button-press-event",
                    G_CALLBACK(OnMouseDown), this);
   gfx::RemoveAllChildren(vbox_.get());
-  gtk_box_pack_start(GTK_BOX(vbox_.get()), content_view_, TRUE, TRUE, 0);
   return view;
 }
 
@@ -184,6 +183,12 @@ void WebContentsViewGtk::RestoreFocus() {
   NOTIMPLEMENTED() << " --  need to restore the focus position on this page.";
 }
 
+void WebContentsViewGtk::SetChildSize(RenderWidgetHostView* rwh_view) {
+  // Packing the gtk widget in a container will cause a configure-event to be
+  // sent to the widget.
+  gtk_box_pack_start(GTK_BOX(vbox_.get()), content_view_, TRUE, TRUE, 0);
+}
+
 void WebContentsViewGtk::UpdateDragCursor(bool is_drop_target) {
   NOTIMPLEMENTED();
 }