Add ViewObserver to View for view updates

ui/views/view_unittest.cc

Index: ui/views/view_unittest.cc
diff --git a/ui/views/view_unittest.cc b/ui/views/view_unittest.cc
index e9af12ad5a964d0a67207326d15e99dbd2163f12..2141dbf5ffa09cb12429633095011826ad091e77 100644
--- a/ui/views/view_unittest.cc
+++ b/ui/views/view_unittest.cc
@@ -41,6 +41,7 @@
 #include "ui/views/controls/textfield/textfield.h"
 #include "ui/views/focus/view_storage.h"
 #include "ui/views/test/views_test_base.h"
+#include "ui/views/view_observer.h"
 #include "ui/views/widget/native_widget.h"
 #include "ui/views/widget/root_view.h"
 #include "ui/views/window/dialog_client_view.h"
@@ -4577,4 +4578,149 @@ TEST_F(ViewTest, CrashOnAddFromFromOnNativeThemeChanged) {
   EXPECT_TRUE(v->on_native_theme_changed_called());
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// Observer tests.
+////////////////////////////////////////////////////////////////////////////////
+
+class ViewObserverTest : public ViewTest, public ViewObserver {
+ public:
+  ViewObserverTest()
+      : view_visibility_changed_(nullptr),
+        view_enabled_changed_(nullptr),
+        view_bounds_changed_(nullptr),
+        view_reordered_(nullptr) {}
+
+  ~ViewObserverTest() override {}
+
+  // ViewObserver:
+  void OnViewParentChanged(View* target, View* old_parent) override {
+    ViewParentChangedDetails details;
+    details.target = target;
+    details.old_parent = old_parent;
+    details.new_parent = target->parent();
+    views_parent_changed_details_.push_back(details);
+  }
+
+  void OnViewVisibilityChanged(View* view) override {
+    view_visibility_changed_ = view;
+  }
+
+  void OnViewEnabledChanged(View* view) override {
+    view_enabled_changed_ = view;
+  }
+
+  void OnViewBoundsChanged(View* view) override { view_bounds_changed_ = view; }
+
+  void OnChildViewReordered(View* view) override { view_reordered_ = view; }
+
+  bool DidChangeParent(View* target, View* old_parent, View* new_parent) {
+    for (auto& details : views_parent_changed_details_) {
+      if (details.target == target && details.old_parent == old_parent &&
+          details.new_parent == new_parent)
+        return true;
+    }
+    return false;
+  }
+
+  void reset() {
+    views_parent_changed_details_.clear();
+    view_visibility_changed_ = nullptr;
+    view_enabled_changed_ = nullptr;
+    view_bounds_changed_ = nullptr;
+    view_reordered_ = nullptr;
+  }
+
+  std::unique_ptr<View> NewView() {
+    auto view = base::MakeUnique<View>();
+    view->AddObserver(this);
+    return view;
+  }
+
+  int views_parent_changed_times() const {
+    return static_cast<int>(views_parent_changed_details_.size());
+  }
+  const View* view_visibility_changed() const {
+    return view_visibility_changed_;
+  }
+  const View* view_enabled_changed() const { return view_enabled_changed_; }
+  const View* view_bounds_changed() const { return view_bounds_changed_; }
+  const View* view_reordered() const { return view_reordered_; }
+
+ private:
+  struct ViewParentChangedDetails {
+    View* target;
+    View* old_parent;
+    View* new_parent;
+  };
+  std::vector<ViewParentChangedDetails> views_parent_changed_details_;
+  View* view_visibility_changed_;
+  View* view_enabled_changed_;
+  View* view_bounds_changed_;
+  View* view_reordered_;
+
+  DISALLOW_COPY_AND_ASSIGN(ViewObserverTest);
+};
+
+TEST_F(ViewObserverTest, ViewParentChanged) {
+  std::unique_ptr<View> parent1 = NewView();
+  std::unique_ptr<View> parent2 = NewView();
+  std::unique_ptr<View> child_view = NewView();
+
+  parent1->AddChildView(child_view.get());
+  EXPECT_EQ(1, views_parent_changed_times());
+  EXPECT_TRUE(DidChangeParent(child_view.get(), nullptr, parent1.get()));
+  reset();
+
+  // Removed from parent1, added to parent2
+  parent2->AddChildView(child_view.get());
+  EXPECT_EQ(2, views_parent_changed_times());
+  EXPECT_TRUE(DidChangeParent(child_view.get(), parent1.get(), nullptr));
+  EXPECT_TRUE(DidChangeParent(child_view.get(), nullptr, parent2.get()));
+
+  reset();
+
+  parent2->RemoveChildView(child_view.get());
+  EXPECT_EQ(1, views_parent_changed_times());
+  EXPECT_TRUE(DidChangeParent(child_view.get(), parent2.get(), nullptr));
+}
+
+TEST_F(ViewObserverTest, ViewVisibilityChanged) {
+  std::unique_ptr<View> view = NewView();
+  view->SetVisible(false);
+  EXPECT_EQ(view.get(), view_visibility_changed());
+  EXPECT_EQ(false, view->visible());
+}
+
+TEST_F(ViewObserverTest, ViewEnabledChanged) {
+  std::unique_ptr<View> view = NewView();
+  view->SetEnabled(false);
+  EXPECT_EQ(view.get(), view_enabled_changed());
+  EXPECT_EQ(false, view->enabled());
+}
+
+TEST_F(ViewObserverTest, ViewBoundsChanged) {
+  std::unique_ptr<View> view = NewView();
+  gfx::Rect bounds(2, 2, 2, 2);
+  view->SetBoundsRect(bounds);
+  EXPECT_EQ(view.get(), view_bounds_changed());
+  EXPECT_EQ(bounds, view->bounds());
+
+  reset();
+
+  gfx::Rect new_bounds(1, 1, 1, 1);
+  view->SetBoundsRect(new_bounds);
+  EXPECT_EQ(view.get(), view_bounds_changed());
+  EXPECT_EQ(new_bounds, view->bounds());
+}
+
+TEST_F(ViewObserverTest, ChildViewReordered) {
+  std::unique_ptr<View> view = NewView();
+  std::unique_ptr<View> child_view = NewView();
+  std::unique_ptr<View> child_view2 = NewView();
+  view->AddChildView(child_view.get());
+  view->AddChildView(child_view2.get());
+  view->ReorderChildView(child_view2.get(), 0);
+  EXPECT_EQ(child_view2.get(), view_reordered());
+}
+
 }  // namespace views