[ash-md] Doesn't recreate a rounded rect mask for overview windows

ui/compositor/layer_unittest.cc

 // Copyright (c) 2012 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 "ui/compositor/layer.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 615 matching lines @@
   DrawTreeLayerDelegate d3(l3->bounds());
   l3->set_delegate(&d3);
 
   l2->SchedulePaint(gfx::Rect(5, 5, 5, 5));
   WaitForDraw();
   EXPECT_FALSE(d1.painted());
   EXPECT_TRUE(d2.painted());
   EXPECT_FALSE(d3.painted());
 }
 
+// Tests that scheduling paint on a layer with a mask updates the mask.
+TEST_F(LayerWithRealCompositorTest, SchedulePaintUpdatesMask) {
+  std::unique_ptr<Layer> layer(
+      CreateColorLayer(SK_ColorRED, gfx::Rect(20, 20, 400, 400)));
+  std::unique_ptr<Layer> mask_layer(CreateLayer(ui::LAYER_TEXTURED));
+  mask_layer->SetBounds(gfx::Rect(layer->GetTargetBounds().size()));
+  layer->SetMaskLayer(mask_layer.get());
+
+  GetCompositor()->SetRootLayer(layer.get());
+  WaitForDraw();
+
+  DrawTreeLayerDelegate d1(layer->bounds());
+  layer->set_delegate(&d1);
+  DrawTreeLayerDelegate d2(mask_layer->bounds());
+  mask_layer->set_delegate(&d2);
+
+  layer->SchedulePaint(gfx::Rect(5, 5, 5, 5));
+  WaitForDraw();
+  EXPECT_TRUE(d1.painted());
+  EXPECT_TRUE(d2.painted());
+}
+
 // Tests no-texture Layers.
 // Create this hierarchy:
 // L1 - red
 // +-- L2 - NO TEXTURE
 // |   +-- L3 - yellow
 // +-- L4 - magenta
 //
 TEST_F(LayerWithRealCompositorTest, HierarchyNoTexture) {
   std::unique_ptr<Layer> l1(
       CreateColorLayer(SK_ColorRED, gfx::Rect(20, 20, 400, 400)));
@@ skipping 1258 matching lines @@
   root->SetOpacity(0.5f);
   WaitForSwap();
   EXPECT_EQ(1u, animation_observer.animation_step_count());
 
   EXPECT_FALSE(animation_observer.shutdown());
   ResetCompositor();
   EXPECT_TRUE(animation_observer.shutdown());
 }
 
 }  // namespace ui