ash: Clean up system background layer.

ui/views/widget/desktop_root_window_host_win.cc

Index: ui/views/widget/desktop_root_window_host_win.cc
diff --git a/ui/views/widget/desktop_root_window_host_win.cc b/ui/views/widget/desktop_root_window_host_win.cc
index 4cdaa679c2cb1438ac777dca8fce4c4785b6e347..4df767ccb5ee699972418da23155f5ebcbed28d8 100644
--- a/ui/views/widget/desktop_root_window_host_win.cc
+++ b/ui/views/widget/desktop_root_window_host_win.cc
@@ -402,9 +402,18 @@ void DesktopRootWindowHostWin::MoveCursorTo(const gfx::Point& location) {
 void DesktopRootWindowHostWin::SetFocusWhenShown(bool focus_when_shown) {
 }
 
+bool DesktopRootWindowHostLinux::CopyAreaToSkCanvas(
+    const gfx::Rect& source_bounds,
+    const gfx::Point& dest_offset,
+    SkCanvas* canvas) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 bool DesktopRootWindowHostWin::GrabSnapshot(
       const gfx::Rect& snapshot_bounds,
       std::vector<unsigned char>* png_representation) {
+  NOTIMPLEMENTED();
   return false;
 }