Update from https://crrev.com/319330
- New chromium clang rules require explicit external destructors so
  system/lib added for MessagePipe, DataPipe and SharedBuffer
- New chromium clang rules require override and no virtual in
  declarations, so many files updated.
- cc_strip_video patch updated.

BUG=
R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/988693005
diff --git a/examples/wm_flow/wm/frame_controller.h b/examples/wm_flow/wm/frame_controller.h
index e251c76..025b1c0 100644
--- a/examples/wm_flow/wm/frame_controller.h
+++ b/examples/wm_flow/wm/frame_controller.h
@@ -36,7 +36,7 @@
                   mojo::View* view,
                   mojo::View** app_view,
                   window_manager::WindowManagerApp* window_manager_app);
-  virtual ~FrameController();
+  ~FrameController() override;
 
   // mojo::InterfaceFactory<examples::WindowFrameHost> implementation.
   void Create(