Supporting shrinking/enlarging for notifications

ui/message_center/views/toast_contents_view.cc

Index: ui/message_center/views/toast_contents_view.cc
diff --git a/ui/message_center/views/toast_contents_view.cc b/ui/message_center/views/toast_contents_view.cc
index 8de495db1c1afc09d6beda2af684d2db9684e58f..4137aa42600a38b930d98f7dc8e41f14c31b4811 100644
--- a/ui/message_center/views/toast_contents_view.cc
+++ b/ui/message_center/views/toast_contents_view.cc
@@ -77,8 +77,7 @@ void ToastContentsView::SetContents(MessageView* view,
   bool already_has_contents = child_count() > 0;
   RemoveAllChildViews(true);
   AddChildView(view);
-  preferred_size_ = GetToastSizeForView(view);
-  Layout();
+  UpdatePreferredSize();
 
   // If it has the contents already, this invocation means an update of the
   // popup toast, and the new contents should be read through a11y feature.
@@ -93,11 +92,7 @@ void ToastContentsView::UpdateContents(const Notification& notification,
   DCHECK_GT(child_count(), 0);
   MessageView* message_view = static_cast<MessageView*>(child_at(0));
   message_view->UpdateWithNotification(notification);
-  gfx::Size new_size = GetToastSizeForView(message_view);
-  if (preferred_size_ != new_size) {
-    preferred_size_ = new_size;
-    Layout();
-  }
+  UpdatePreferredSize();
   if (a11y_feedback_for_updates)
     NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, false);
 }
@@ -126,23 +121,32 @@ void ToastContentsView::CloseWithAnimation() {
 }
 
 void ToastContentsView::SetBoundsInstantly(gfx::Rect new_bounds) {
-  if (new_bounds == bounds())
-    return;
+  DCHECK(new_bounds.size().width() <= preferred_size_.width() &&
+         new_bounds.size().height() <= preferred_size_.height())
+      << "we can not display widget bigger than notification";
 
-  origin_ = new_bounds.origin();
   if (!GetWidget())
     return;
+
+  if (new_bounds == GetWidget()->GetWindowBoundsInScreen())
+    return;
+
+  origin_ = new_bounds.origin();
   GetWidget()->SetBounds(new_bounds);
 }
 
 void ToastContentsView::SetBoundsWithAnimation(gfx::Rect new_bounds) {
-  if (new_bounds == bounds())
-    return;
+  DCHECK(new_bounds.size().width() <= preferred_size_.width() &&
+         new_bounds.size().height() <= preferred_size_.height())
+      << "we can not display widget bigger than notification";
 
-  origin_ = new_bounds.origin();
   if (!GetWidget())
     return;
 
+  if (new_bounds == animated_bounds_end_)
+    return;
+
+  origin_ = new_bounds.origin();
   // This picks up the current bounds, so if there was a previous animation
   // half-done, the next one will pick up from the current location.
   // This is the only place that should query current location of the Widget
@@ -288,6 +292,24 @@ gfx::Size ToastContentsView::GetPreferredSize() const {
   return child_count() ? GetToastSizeForView(child_at(0)) : gfx::Size();
 }
 
+void ToastContentsView::UpdatePreferredSize() {
+  DCHECK_GT(child_count(), 0);
+  gfx::Size new_size = GetToastSizeForView(child_at(0));
+  if (preferred_size_ == new_size)
+    return;
+  // Growing notifications instantly can cause notification's to overlap
+  // And shrinking with animation, leaves area, where nothing is drawn
+  const bool change_instantly = preferred_size_.width() > new_size.width() ||
+                                preferred_size_.height() > new_size.height();
+  preferred_size_ = new_size;
+  Layout();
+  if (change_instantly) {
+    SetBoundsInstantly(bounds());
+    return;
+  }
+  SetBoundsWithAnimation(bounds());
+}
+
 void ToastContentsView::GetAccessibleState(ui::AXViewState* state) {
   if (child_count() > 0)
     child_at(0)->GetAccessibleState(state);