Updates embedded surface layer visibility when window is reparented

When the window is reparented from a hidden parent to a visible one,
the embedded surface layer visibility should be updated accordingly.

BUG=956822, 866622
TEST=Manually (see bug), and added a test.

Change-Id: Ib92ddf80f9889d2e001962ca4e3773b88c29f4aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1585235
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654606}

ui/aura/BUILD.gn

@@ -395,6 +395,7 @@ test("aura_unittests") {
     "gestures/gesture_recognizer_unittest.cc",
     "mouse_location_manager_unittest.cc",
     "mus/client_side_window_move_handler_unittest.cc",
+    "mus/client_surface_embedder_unittest.cc",
     "mus/drag_drop_controller_mus_unittest.cc",
     "mus/focus_synchronizer_unittest.cc",
     "mus/gesture_synchronizer_unittest.cc",

ui/aura/mus/client_surface_embedder.cc

@@ -67,10 +67,22 @@ viz::SurfaceId ClientSurfaceEmbedder::GetSurfaceId() const {
   return id ? *id : viz::SurfaceId();
 }
 
+ui::Layer* ClientSurfaceEmbedder::GetSurfaceLayerForTesting() const {
+  return surface_layer_owner_->layer();
+}
+
 void ClientSurfaceEmbedder::OnWindowVisibilityChanged(Window* window,
                                                       bool visible) {
   if (window->Contains(window_))
     surface_layer_owner_->layer()->SetVisible(GetTargetVisibility(window_));
 }
 
+void ClientSurfaceEmbedder::OnWindowHierarchyChanged(
+    const HierarchyChangeParams& params) {
+  // Window may change visibility as a result of being reparented to a different
+  // parent window with different visibility.
+  if (params.target == window_)
+    surface_layer_owner_->layer()->SetVisible(GetTargetVisibility(window_));
+}
+
 }  // namespace aura

ui/aura/mus/client_surface_embedder.h

@@ -13,6 +13,7 @@
 
 namespace ui {
 class LayerOwner;
+class Layer;
 }
 
 namespace viz {
@@ -38,9 +39,12 @@ class AURA_EXPORT ClientSurfaceEmbedder : public WindowObserver {
   // Returns the SurfaceId, empty if SetSurfaceId() has not been called yet.
   viz::SurfaceId GetSurfaceId() const;
 
+  ui::Layer* GetSurfaceLayerForTesting() const;
+
  private:
   // aura::WindowObserver:
   void OnWindowVisibilityChanged(Window* window, bool visible) override;
+  void OnWindowHierarchyChanged(const HierarchyChangeParams& params) override;
 
   // The window which embeds the client.
   Window* window_;

ui/aura/mus/client_surface_embedder_unittest.cc

+// Copyright 2019 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/aura/mus/client_surface_embedder.h"
+
+#include "ui/aura/test/aura_mus_test_base.h"
+#include "ui/aura/test/mus/window_port_mus_test_helper.h"
+
+namespace aura {
+
+namespace {
+
+using ClientSurfaceEmbedderTest = test::AuraMusClientTestBase;
+
+// Test that reparenting a window from a hidden parent to a visible one updates
+// the embedded surface layer visibility. https://crbug.com/956822.
+TEST_F(ClientSurfaceEmbedderTest, SurfaceVisibility) {
+  std::unique_ptr<Window> parent1(
+      CreateNormalWindow(100, root_window(), nullptr));
+  parent1->Show();
+  std::unique_ptr<Window> parent2(
+      CreateNormalWindow(200, root_window(), nullptr));
+  parent2->Show();
+  std::unique_ptr<Window> window(
+      CreateNormalWindow(10, parent1.get(), nullptr));
+  window->Show();
+
+  WindowPortMusTestHelper(window.get()).SimulateEmbedding();
+
+  ClientSurfaceEmbedder* client_surface_embedder =
+      WindowPortMusTestHelper(window.get()).GetClientSurfaceEmbedder();
+
+  EXPECT_TRUE(window->IsVisible());
+  EXPECT_TRUE(client_surface_embedder->GetSurfaceLayerForTesting()
+                  ->GetTargetVisibility());
+
+  // Hide the current parent and expect the visibility will be updated.
+  parent1->Hide();
+  EXPECT_FALSE(window->IsVisible());
+  EXPECT_FALSE(client_surface_embedder->GetSurfaceLayerForTesting()
+                   ->GetTargetVisibility());
+
+  // Reparent the window from the hidden parent to the visible one.
+  parent2->AddChild(window.get());
+  EXPECT_TRUE(window->IsVisible());
+  EXPECT_TRUE(client_surface_embedder->GetSurfaceLayerForTesting()
+                  ->GetTargetVisibility());
+}
+
+}  // namespace
+
+}  // namespace aura