View::SetVisible() notifies layout manager.

Explicit calls to View::SetVisible() outside of LayoutManager::Layout()
will cause the view's parent's layout manager (if there is one) to be
notified. This way, we can treat someone calling SetVisible() as a state
change for the layout manager, perpendicular to any changes the layout
manager itself makes to the visibility of child views (for example, if
it decides to hide them because there is not enough space to display
them).

Also, reordering child views invalidates layout. It should always have.

Bug: 898632
Change-Id: I47382e5efe348b63a7dda7b6e493f55ac5bd74fb
Reviewed-on: https://chromium-review.googlesource.com/c/1368274Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614832}

ui/views/layout/layout_manager.cc

@@ -4,6 +4,7 @@
 
 #include "ui/views/layout/layout_manager.h"
 
+#include "base/auto_reset.h"
 #include "ui/views/view.h"
 
 namespace views {
@@ -39,4 +40,12 @@ void LayoutManager::ViewAdded(View* host, View* view) {
 void LayoutManager::ViewRemoved(View* host, View* view) {
 }
 
+void LayoutManager::ViewVisibilitySet(View* host, View* view, bool visible) {}
+
+void LayoutManager::SetViewVisibility(View* view, bool visible) {
+  DCHECK_EQ(view->parent()->GetLayoutManager(), this);
+  base::AutoReset<View*> setter(&view_setting_visibility_on_, view);
+  view->SetVisible(visible);
+}
+
 }  // namespace views

ui/views/layout/layout_manager.h

@@ -71,6 +71,20 @@ class VIEWS_EXPORT LayoutManager {
   // been installed on. This function allows the LayoutManager to cleanup any
   // state it has kept specific to a View.
   virtual void ViewRemoved(View* host, View* view);
+
+  // Called when View::SetVisible() is called by external code. Classes derived
+  // from LayoutManager can call SetViewVisibility() below to avoid triggering
+  // this event.
+  virtual void ViewVisibilitySet(View* host, View* view, bool visible);
+
+ protected:
+  // Sets the visibility of a view without triggering ViewVisibilitySet().
+  // During Layout(), use this method instead of View::SetVisibility().
+  void SetViewVisibility(View* view, bool visible);
+
+ private:
+  friend class views::View;
+  View* view_setting_visibility_on_ = nullptr;
 };
 
 }  // namespace views

ui/views/view.cc

@@ -266,6 +266,7 @@ void View::ReorderChildView(View* view, int index) {
     observer.OnChildViewReordered(this, view);
 
   ReorderLayers();
+  InvalidateLayout();
 }
 
 void View::RemoveChildView(View* view) {
@@ -439,6 +440,12 @@ int View::GetHeightForWidth(int w) const {
 }
 
 void View::SetVisible(bool visible) {
+  if (parent_) {
+    LayoutManager* const layout_manager = parent_->GetLayoutManager();
+    if (layout_manager && layout_manager->view_setting_visibility_on_ != this)
+      layout_manager->ViewVisibilitySet(parent_, this, visible);
+  }
+
   if (visible != visible_) {
     // If the View is currently visible, schedule paint to refresh parent.
     // TODO(beng): not sure we should be doing this if we have a layer.