Add MetalayerMode to the palette.

ash/test/test_palette_delegate.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/test/test_palette_delegate.h"
 
 namespace ash {
 
 TestPaletteDelegate::TestPaletteDelegate() {}
 
@@ skipping 26 matching lines @@
   ++take_screenshot_count_;
 }
 
 void TestPaletteDelegate::TakePartialScreenshot(const base::Closure& done) {
   ++take_partial_screenshot_count_;
   partial_screenshot_done_ = done;
 }
 
 void TestPaletteDelegate::CancelPartialScreenshot() {}
 
+bool TestPaletteDelegate::IsMetalayerSupported() {
+  return false;
+}
+
+void TestPaletteDelegate::ShowMetalayer(const base::Closure& closed) {}
+
+void TestPaletteDelegate::HideMetalayer() {}
+
 }  // namespace ash