Collapse older notification popups.

According to UX, in addition to expanding the latest notification,
older notification popups should be collapsed.

See the screencast:
- Without this CL:
  http://go/scrcast/NTY3OTAwNjEyOTA2MTg4OHxjMjY3MGMxMS0xNw
- With this CL: http://go/scrcast/NTY0MjAyMzc3NjI4ODc2OHxhYjBmNWQ4Yy02NA

TEST=NotificationViewMDTest.ExpandLongMessage
BUG=792582

Change-Id: Ie6693386acda5a47405350822a48b4b0a279029f
Reviewed-on: https://chromium-review.googlesource.com/830998Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525034}

ui/message_center/views/message_popup_collection.cc

@@ -127,6 +127,26 @@ void MessagePopupCollection::UpdateWidgets() {
       alignment_delegate_->IsPrimaryDisplayForNotification();
 #endif
 
+  // Check if the popups contain a new notification.
+  bool has_new_toasts = false;
+  for (auto* popup : popups) {
+    if (!FindToast(popup->id())) {
+      has_new_toasts = true;
+      break;
+    }
+  }
+
+  // If a new notification is found, collapse all existing notifications
+  // beforehand.
+  if (has_new_toasts) {
+    for (auto* toast : toasts_) {
+      if (toast->message_view()->IsMouseHovered() ||
+          toast->message_view()->manually_expanded_or_collapsed())
+        continue;
+      toast->message_view()->SetExpanded(false);
+    }
+  }
+
   // Iterate in the reverse order to keep the oldest toasts on screen. Newer
   // items may be ignored if there are no room to place them.
   for (NotificationList::PopupNotifications::const_reverse_iterator iter =

ui/message_center/views/message_view.h

@@ -99,6 +99,10 @@ class MESSAGE_CENTER_EXPORT MessageView
   void set_force_disable_pinned() { force_disable_pinned_ = true; }
 #endif
 
+  bool manually_expanded_or_collapsed() const {
+    return manually_expanded_or_collapsed_;
+  }
+
  protected:
   // Creates and add close button to view hierarchy when necessary. Derived
   // classes should call this after its view hierarchy is populated to ensure
@@ -112,6 +116,10 @@ class MESSAGE_CENTER_EXPORT MessageView
   views::View* background_view() { return background_view_; }
   views::ScrollView* scroller() { return scroller_; }
 
+  void set_manually_expanded_or_collapsed() {
+    manually_expanded_or_collapsed_ = true;
+  }
+
  private:
   std::string notification_id_;
   views::View* background_view_ = nullptr;  // Owned by views hierarchy.
@@ -125,6 +133,10 @@ class MESSAGE_CENTER_EXPORT MessageView
   // pinned regardless of the value of |pinned_|.
   bool force_disable_pinned_ = false;
 
+  // True if the notification is expanded/collapsed by user interaction.
+  // If true, MessagePopupCollection will not auto-collapse the notification.
+  bool manually_expanded_or_collapsed_ = false;
+
   std::unique_ptr<views::Painter> focus_painter_;
 
   views::SlideOutController slide_out_controller_;

ui/message_center/views/notification_view_md.cc

@@ -655,6 +655,7 @@ void NotificationViewMD::ButtonPressed(views::Button* sender,
   // |expand_button| can be focused by TAB.
   if (sender == header_row_) {
     if (IsExpandable()) {
+      set_manually_expanded_or_collapsed();
       ToggleExpanded();
       Layout();
       SchedulePaint();

ui/message_center/views/notification_view_md_unittest.cc

@@ -637,6 +637,20 @@ TEST_F(NotificationViewMDTest, ExpandLongMessage) {
   EXPECT_EQ(collapsed_height, notification_view()->message_view_->height());
   EXPECT_EQ(collapsed_preferred_height,
             notification_view()->GetPreferredSize().height());
+
+  // Test |manually_expanded_or_collapsed| being set when the toggle is done by
+  // user interaction.
+  EXPECT_FALSE(notification_view()->manually_expanded_or_collapsed());
+
+  // Construct a mouse click event 1 pixel inside the header.
+  gfx::Point done_cursor_location(1, 1);
+  views::View::ConvertPointToScreen(notification_view()->header_row_,
+                                    &done_cursor_location);
+  ui::test::EventGenerator generator(widget()->GetNativeWindow());
+  generator.MoveMouseTo(done_cursor_location);
+  generator.ClickLeftButton();
+
+  EXPECT_TRUE(notification_view()->manually_expanded_or_collapsed());
 }
 
 TEST_F(NotificationViewMDTest, TestAccentColor) {

ui/message_center/views/toast_contents_view.cc

@@ -83,6 +83,7 @@ ToastContentsView::~ToastContentsView() {
 
 void ToastContentsView::SetContents(MessageView* view,
                                     bool a11y_feedback_for_updates) {
+  message_view_ = view;
   bool already_has_contents = child_count() > 0;
   RemoveAllChildViews(true);
   AddChildView(view);

ui/message_center/views/toast_contents_view.h

@@ -80,6 +80,8 @@ class MESSAGE_CENTER_EXPORT ToastContentsView
 
   const std::string& id() const { return id_; }
 
+  MessageView* message_view() { return message_view_; }
+
   // Overridden from views::View:
   void OnMouseEntered(const ui::MouseEvent& event) override;
   void OnMouseExited(const ui::MouseEvent& event) override;
@@ -141,6 +143,9 @@ class MESSAGE_CENTER_EXPORT ToastContentsView
   gfx::Point origin_;
   gfx::Size preferred_size_;
 
+  // Weak reference to the MessageView.
+  MessageView* message_view_ = nullptr;
+
   DISALLOW_COPY_AND_ASSIGN(ToastContentsView);
 };