Add ripple effect to action in expand button.

ui/message_center/views/notification_header_view.cc

Index: ui/message_center/views/notification_header_view.cc
diff --git a/ui/message_center/views/notification_header_view.cc b/ui/message_center/views/notification_header_view.cc
index 7a4fa5d9d8a4b62f7af2b273010ba832839a332a..9e7b1ecfebf5de3f17f6e631bd23134168793310 100644
--- a/ui/message_center/views/notification_header_view.cc
+++ b/ui/message_center/views/notification_header_view.cc
@@ -43,6 +43,51 @@ constexpr float kInkDropRippleVisibleOpacity = 0.08f;
 // Highlight (hover) ink drop opacity of action buttons.
 constexpr float kInkDropHighlightVisibleOpacity = 0.08f;
 
+class ExpandButton : public views::ImageButton, public views::ButtonListener {

[yoshiki, 2017/07/03 06:26:49]

BTW, why is it inheriting a button? Although this doesn't accept mouse event and
key events, is it necessary to be a button?

[tetsui, 2017/07/03 07:10:54]

Done.

+ public:
+  ExpandButton(NotificationHeaderView* header);
+  ~ExpandButton() override;
+
+  // ButtonListener override:
+  void ButtonPressed(Button* sender, const ui::Event& event) override;
+
+ protected:
+  // ImageButton override:
+  void OnMouseEvent(ui::MouseEvent* event) override;
+  void OnKeyEvent(ui::KeyEvent* event) override;
+
+ private:
+  NotificationHeaderView* header_;
+};
+
+ExpandButton::ExpandButton(NotificationHeaderView* header)
+    : views::ImageButton(this), header_(header) {
+  SetImage(views::Button::STATE_NORMAL,
+           gfx::CreateVectorIcon(kNotificationExpandMoreIcon, kExpandIconSize,
+                                 gfx::kChromeIconGrey));
+  SetFocusForPlatform();
+  SetFocusPainter(views::Painter::CreateSolidFocusPainter(
+      kFocusBorderColor, gfx::Insets(1, 2, 2, 2)));
+}
+
+ExpandButton::~ExpandButton() = default;
+
+void ExpandButton::ButtonPressed(Button* sender, const ui::Event& event) {
+  // No need to handle event here because raw OnMouseEvent and OnKeyEvent are
+  // forwarded to NotificationHeaderView.
+}
+
+void ExpandButton::OnMouseEvent(ui::MouseEvent* event) {
+  views::View* source = this;

[yoshiki, 2017/07/03 06:26:49]

Can this method be empty? I think if you don't anything in this method, the
event will propagate to the parent view (in this case, header view)
automatically.

[tetsui, 2017/07/03 07:10:54]

Done.

+  views::View* target = header_;
+  ui::MouseEvent converted_event(*event, source, target);
+  header_->OnMouseEvent(&converted_event);
+}
+
+void ExpandButton::OnKeyEvent(ui::KeyEvent* event) {
+  header_->OnKeyEvent(event);
+}
+
 }  // namespace
 
 NotificationHeaderView::NotificationHeaderView(views::ButtonListener* listener)
@@ -101,14 +146,7 @@ NotificationHeaderView::NotificationHeaderView(views::ButtonListener* listener)
   app_info_container->AddChildView(summary_text_view_);
 
   // Expand button view
-  expand_button_ = new views::ImageButton(listener);
-  expand_button_->SetImage(
-      views::Button::STATE_NORMAL,
-      gfx::CreateVectorIcon(kNotificationExpandMoreIcon, kExpandIconSize,
-                            gfx::kChromeIconGrey));
-  expand_button_->SetFocusForPlatform();
-  expand_button_->SetFocusPainter(views::Painter::CreateSolidFocusPainter(
-      kFocusBorderColor, gfx::Insets(1, 2, 2, 2)));
+  expand_button_ = new ExpandButton(this);
   app_info_container->AddChildView(expand_button_);
 
   // Spacer between left-aligned views and right-aligned views
@@ -157,6 +195,11 @@ void NotificationHeaderView::ClearProgress() {
 }
 
 void NotificationHeaderView::SetExpandButtonEnabled(bool enabled) {
+  // SetInkDropMode iff. the visibility changed.
+  // Otherwise, the ink drop animation cannot finish.
+  if (expand_button_->visible() != enabled)
+    SetInkDropMode(enabled ? InkDropMode::ON : InkDropMode::OFF);
+
   expand_button_->SetVisible(enabled);
 }