Notification: Only start hot mode when needed.

In Nearby Share, we encounter a problem of an image notification not
showing entirely. This happens because of this use case:
- The popup notification A is showing and we hover over that
notification.
- Notification A is then removed automatically to show notification B
with image.
- Notification B with image is cut off because we accidentally enter hot
mode.

This CL added a check so that we only start hot mode when necessary
(when a notification is closed by an actual user).

Fixed: 1154741
Change-Id: I306e66e92d2e28ba11cb1526089789ad1eb9331b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2591267
Commit-Queue: Andre Le <leandre@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843219}

ui/message_center/views/message_popup_collection.cc

@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "base/timer/timer.h"
 #include "ui/gfx/animation/linear_animation.h"
 #include "ui/gfx/animation/tween.h"
 #include "ui/message_center/message_center.h"
@@ -25,6 +26,9 @@ constexpr base::TimeDelta kFadeInFadeOutDuration =
 constexpr base::TimeDelta kMoveDownDuration =
     base::TimeDelta::FromMilliseconds(120);
 
+// Time to wait until we reset |recently_closed_by_user_|.
+constexpr base::TimeDelta kWaitForReset = base::TimeDelta::FromSeconds(10);
+
 }  // namespace
 
 MessagePopupCollection::MessagePopupCollection()
@@ -132,9 +136,22 @@ void MessagePopupCollection::OnNotificationAdded(
 void MessagePopupCollection::OnNotificationRemoved(
     const std::string& notification_id,
     bool by_user) {
+  if (by_user) {
+    recently_closed_by_user_ = true;
+    recently_closed_by_user_timer_ = std::make_unique<base::OneShotTimer>();
+    recently_closed_by_user_timer_->Start(
+        FROM_HERE, kWaitForReset,
+        base::BindOnce(&MessagePopupCollection::ResetRecentlyClosedByUser,
+                       base::Unretained(this)));
+  }
   Update();
 }
 
+void MessagePopupCollection::ResetRecentlyClosedByUser() {
+  recently_closed_by_user_ = false;
+  recently_closed_by_user_timer_.reset();
+}
+
 void MessagePopupCollection::OnNotificationUpdated(
     const std::string& notification_id) {
   if (is_updating_)
@@ -272,7 +289,9 @@ void MessagePopupCollection::TransitionToAnimation() {
     MarkRemovedPopup();
 
     // Start hot mode to allow a user to continually close many notifications.
-    StartHotMode();
+    // Only start hot mode if there's a notification recently closed by user.
+    if (recently_closed_by_user_)
+      StartHotMode();
 
     if (CloseTransparentPopups()) {
       // If the popup is already transparent, skip FADE_OUT.

ui/message_center/views/message_popup_collection.h

@@ -15,6 +15,10 @@
 #include "ui/message_center/message_center_observer.h"
 #include "ui/views/widget/widget.h"
 
+namespace base {
+class OneShotTimer;
+}  // namespace base
+
 namespace gfx {
 class LinearAnimation;
 }  // namespace gfx
@@ -255,6 +259,10 @@ class MESSAGE_CENTER_EXPORT MessagePopupCollection
   // When |inverse_| is false, it's same as popup_items_[i].
   PopupItem* GetPopupItem(size_t index_from_top);
 
+  // Reset |recently_closed_by_user_| to false. Used by
+  // |recently_closed_by_user_timer_|
+  void ResetRecentlyClosedByUser();
+
   // Animation state. See the comment of State.
   State state_ = State::IDLE;
 
@@ -279,6 +287,14 @@ class MESSAGE_CENTER_EXPORT MessagePopupCollection
 
   // Hot mode related variables. See StartHotMode() and ResetHotMode().
 
+  // True if a notification is just closed by an user and hot mode should start.
+  // After a brief moment, this boolean will be set to false by the timer.
+  bool recently_closed_by_user_ = false;
+
+  // Timer that fires to reset |recently_closed_by_user_| to false, indicating
+  // that we should not start hot mode.
+  std::unique_ptr<base::OneShotTimer> recently_closed_by_user_timer_;
+
   // True if the close button of the popup at |hot_index_| is hot.
   bool is_hot_ = false;