Create a LayerDelegate for recreated layers to draw when their content is invalidated.

ui/wm/core/window_util_unittest.cc

Index: ui/wm/core/window_util_unittest.cc
diff --git a/ui/wm/core/window_util_unittest.cc b/ui/wm/core/window_util_unittest.cc
index 72516bec4217ea1daf4352a96b6fefcddb2d7dab..68ecb4b600fced5bdc8fdb40fc39a5672a6319e7 100644
--- a/ui/wm/core/window_util_unittest.cc
+++ b/ui/wm/core/window_util_unittest.cc
@@ -11,8 +11,61 @@
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_tree_owner.h"
+#include "ui/compositor/paint_context.h"
 
 namespace wm {
+namespace {
+
+// Used to check if the delegate for recreated layer is created for
+// the correct delegate.
+class TestLayerDelegate : public ui::LayerDelegate {
+ public:
+  explicit TestLayerDelegate(ui::LayerDelegate* original_delegate)
+      : original_delegate_(original_delegate) {}
+  ~TestLayerDelegate() override = default;
+
+  // ui::LayerDelegate:
+  void OnPaintLayer(const ui::PaintContext& context) override {}
+  void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override {}
+  void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
+  base::Closure PrepareForLayerBoundsChange() override {
+    return base::Closure();
+  }
+
+  ui::LayerDelegate* original_delegate() { return original_delegate_; }
+
+ private:
+  ui::LayerDelegate* original_delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestLayerDelegate);
+};
+
+// Used to create a TestLayerDelegate for recreated layers.
+class TestLayerDelegateFactory : public ::wm::LayerDelegateFactory {
+ public:
+  TestLayerDelegateFactory() = default;
+  ~TestLayerDelegateFactory() override = default;
+
+  // ::wm::LayerDelegateFactory:
+  ui::LayerDelegate* CreateDelegate(ui::LayerDelegate* delegate) override {
+    TestLayerDelegate* new_delegate = new TestLayerDelegate(delegate);
+    delegates_.push_back(base::WrapUnique(new_delegate));
+    return new_delegate;
+  }
+
+  size_t delegate_count() const { return delegates_.size(); }
+
+  TestLayerDelegate* GetDelegateAt(int index) {
+    return delegates_[index].get();
+  }
+
+ private:
+  std::vector<std::unique_ptr<TestLayerDelegate>> delegates_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestLayerDelegateFactory);
+};
+
+}  // namespace
 
 typedef aura::test::AuraTestBase WindowUtilTest;
 
@@ -32,7 +85,8 @@ TEST_F(WindowUtilTest, RecreateLayers) {
   EXPECT_TRUE(acquired.get());
   EXPECT_EQ(acquired.get(), window11->layer());
 
-  std::unique_ptr<ui::LayerTreeOwner> tree = wm::RecreateLayers(window1.get());
+  std::unique_ptr<ui::LayerTreeOwner> tree =
+      wm::RecreateLayers(window1.get(), nullptr);
 
   // The detached layer should not have the layer that has
   // already been detached.
@@ -49,4 +103,36 @@ TEST_F(WindowUtilTest, RecreateLayers) {
   // Delete the window before the acquired layer is deleted.
   window11.reset();
 }
+
+// Test if the LayerDelegateFactory creates new delegates for
+// recreated layers correctly.
+TEST_F(WindowUtilTest, RecreateLayersWithDelegate) {
+  TestLayerDelegateFactory factory;
+  std::unique_ptr<aura::Window> window1(
+      aura::test::CreateTestWindowWithId(0, NULL));
+  std::unique_ptr<aura::Window> window11(
+      aura::test::CreateTestWindowWithId(1, window1.get()));
+  std::unique_ptr<aura::Window> window12(
+      aura::test::CreateTestWindowWithId(2, window1.get()));
+
+  std::unique_ptr<ui::LayerTreeOwner> tree =
+      wm::RecreateLayers(window1.get(), &factory);
+
+  ASSERT_EQ(3u, factory.delegate_count());
+
+  TestLayerDelegate* new_delegate_1 = factory.GetDelegateAt(0);
+  TestLayerDelegate* new_delegate_11 = factory.GetDelegateAt(1);
+  TestLayerDelegate* new_delegate_12 = factory.GetDelegateAt(2);
+
+  EXPECT_EQ(window1->layer()->delegate(), new_delegate_1->original_delegate());
+  EXPECT_EQ(window11->layer()->delegate(),
+            new_delegate_11->original_delegate());
+  EXPECT_EQ(window12->layer()->delegate(),
+            new_delegate_12->original_delegate());
+
+  EXPECT_EQ(tree->root()->delegate(), new_delegate_1);
+  EXPECT_EQ(tree->root()->children()[0]->delegate(), new_delegate_11);
+  EXPECT_EQ(tree->root()->children()[1]->delegate(), new_delegate_12);
+}
+
 }  // namespace wm