Ensure View invalidates Widget::root_layers_ when LayerOwner::RecreateLayer is invoked

ash/wm/window_state_unittest.cc

 // Copyright 2014 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/wm/window_state.h"
 
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/wm_event.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/window.h"
+#include "ui/views/widget/widget.h"
 
 namespace ash {
 namespace wm {
 namespace {
 
 class AlwaysMaximizeTestState : public WindowState::State {
  public:
   explicit AlwaysMaximizeTestState(WindowStateType initial_state_type)
       : state_type_(initial_state_type) {}
   ~AlwaysMaximizeTestState() override {}
@@ skipping 305 matching lines @@
 
   window_state->Restore();
   EXPECT_FALSE(window_state->IsMaximized());
   EXPECT_NE(work_area.ToString(), window->bounds().ToString());
   EXPECT_TRUE(work_area.Contains(window->bounds()));
 }
 
 // TODO(skuhne): Add more unit test to verify the correctness for the restore
 // operation.
 
+// Tests for correct ownership of window sublayers during crossfade transitions.
+TEST_F(WindowStateTest, RecreateLayersDuringCrossfade) {

[sky, 2015/11/30 16:52:09]

This test is ok, but you're relying on maximize recreating layers. How about
directly calling RecreateLayers?

[tapted, 2015/12/01 04:34:43]

I did this in Patchset 4, but it made the connection to ash/../window_state a
bit tenuous. Also it started looking a lot like the existing test in
view_unittest_aura for wm::RecreateLayers

So I've incorporated the test cases into view_unittest_aura's
ViewAuraTest.RecreateLayersWithWindows - I think this make sense. It also has
the advantage of being run on more platforms, instead of just those running
ash_unittests. PTAL

+  views::Widget* widget = views::Widget::CreateWindowWithContextAndBounds(
+      nullptr, CurrentContext(), gfx::Rect(100, 100, 100, 100));
+
+  views::View* view = new views::View;
+  view->SetBounds(20, 20, 20, 20);
+  widget->GetContentsView()->AddChildView(view);
+  widget->Show();
+
+  EXPECT_EQ(0u, widget->GetRootLayers().size());
+  view->SetPaintToLayer(true);
+  EXPECT_EQ(1u, widget->GetRootLayers().size());
+  ui::Layer* old_layer = widget->GetRootLayers()[0];
+
+  // On Ash, Maximize will trigger WindowState::SetBoundsDirectCrossFade() to
+  // start a crossfade animation after invoking ::wm::RecreateLayers().
+  widget->Maximize();
+
+  EXPECT_EQ(1u, widget->GetRootLayers().size());
+
+  // The layer should be different, since the old layer is in the crossfade.
+  EXPECT_NE(old_layer, widget->GetRootLayers()[0]);
+
+  widget->CloseNow();
+}
+
 }  // namespace wm
 }  // namespace ash