Not submitted - Fixing invalid visibility states with layers which showed up in unittests ...

ash/wm/panels/panel_layout_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/panels/panel_layout_manager.h"
 
 #include <algorithm>
 #include <map>
 
 #include "ash/screen_util.h"
@@ skipping 39 matching lines @@
 const int kCalloutFadeDurationMilliseconds = 50;
 
 // Offset used when sliding panel in/out of the shelf. Used for minimizing,
 // restoring and the initial showing of a panel.
 const int kPanelSlideInOffset = 20;
 
 // Callout arrow dimensions.
 const int kArrowWidth = 18;
 const int kArrowHeight = 9;
 
+// When a window layer gets hidden, and the window remains "logically visible",
+// it is illegal to fade the layer to 0. We therefore use a fraction which is
+// resolving to an alpha of 0 but tells a comparison otherwise.
+const float kWindowLayerNotShown = 0.001f;
+
 class CalloutWidgetBackground : public views::Background {
  public:
   CalloutWidgetBackground() : alignment_(SHELF_ALIGNMENT_BOTTOM) {
   }
 
   virtual void Paint(gfx::Canvas* canvas, views::View* view) const OVERRIDE {
     SkPath path;
     switch (alignment_) {
       case SHELF_ALIGNMENT_BOTTOM:
         path.moveTo(SkIntToScalar(0), SkIntToScalar(0));
@@ skipping 166 matching lines @@
     params.bounds.set_width(kArrowWidth);
     params.bounds.set_height(kArrowHeight);
     // Why do we need this and can_activate = false?
     set_focus_on_creation(false);
     Init(params);
     DCHECK_EQ(GetNativeView()->GetRootWindow(), parent->GetRootWindow());
     views::View* content_view = new views::View;
     background_ = new CalloutWidgetBackground;
     content_view->set_background(background_);
     SetContentsView(content_view);
-    GetNativeWindow()->layer()->SetOpacity(0);
+    GetNativeWindow()->layer()->SetOpacity(kWindowLayerNotShown);
   }
 
   // Weak pointer owned by this widget's content view.
   CalloutWidgetBackground* background_;
 
   DISALLOW_COPY_AND_ASSIGN(PanelCalloutWidget);
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 // PanelLayoutManager public implementation:
@@ skipping 102 matching lines @@
     wm::ReparentTransientChildrenOfChild(child, old_parent, child->parent());
     DCHECK(child->parent()->id() != kShellWindowId_PanelContainer);
     return;
   }
   PanelInfo panel_info;
   panel_info.window = child;
   panel_info.callout_widget = new PanelCalloutWidget(panel_container_);
   if (child != dragged_panel_) {
     // Set the panel to 0 opacity until it has been positioned to prevent it
     // from flashing briefly at position (0, 0).
-    child->layer()->SetOpacity(0);
+    child->layer()->SetOpacity(kWindowLayerNotShown);
     panel_info.slide_in = true;
   }
   panel_windows_.push_back(panel_info);
   child->AddObserver(this);
   wm::GetWindowState(child)->AddObserver(this);
   Relayout();
 }
 
 void PanelLayoutManager::OnWillRemoveWindowFromLayout(aura::Window* child) {
 }
@@ skipping 174 matching lines @@
   panel_slide_settings.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds(kPanelSlideDurationMilliseconds));
   gfx::Rect bounds(panel->bounds());
   bounds.Offset(GetSlideInAnimationOffset(
       shelf_->shelf_widget()->GetAlignment()));
   SetChildBoundsDirect(panel, bounds);
   panel->Hide();
   PanelList::iterator found =
       std::find(panel_windows_.begin(), panel_windows_.end(), panel);
   if (found != panel_windows_.end()) {
-    layer->SetOpacity(0);
+    layer->SetOpacity(kWindowLayerNotShown);
     // The next time the window is visible it should slide into place.
     found->slide_in = true;
   }
   if (wm::IsActiveWindow(panel))
     wm::DeactivateWindow(panel);
   Relayout();
 }
 
 void PanelLayoutManager::RestorePanel(aura::Window* panel) {
   panel->Show();
@@ skipping 275 matching lines @@
                                       panel);
     callout_widget->Show();
 
     ui::Layer* layer = callout_widget->GetNativeWindow()->layer();
     // If the panel is not over the callout position or has just become visible
     // then fade in the callout.
     if ((distance_until_over_panel > 0 || layer->GetTargetOpacity() < 1) &&
         panel->layer()->GetTargetTransform().IsIdentity()) {
       if (distance_until_over_panel > 0 &&
           slide_distance >= distance_until_over_panel) {
-        layer->SetOpacity(0);
+        layer->SetOpacity(kWindowLayerNotShown);
         // If the panel is not yet over the callout, then delay fading in
         // the callout until after the panel should be over it.
         int delay = kPanelSlideDurationMilliseconds *
             distance_until_over_panel / slide_distance;
-        layer->SetOpacity(0);
+        layer->SetOpacity(kWindowLayerNotShown);
         layer->GetAnimator()->StopAnimating();
         layer->GetAnimator()->SchedulePauseForProperties(
             base::TimeDelta::FromMilliseconds(delay),
             ui::LayerAnimationElement::OPACITY);
       }
       {
         ui::ScopedLayerAnimationSettings callout_settings(layer->GetAnimator());
         callout_settings.SetPreemptionStrategy(
             ui::LayerAnimator::REPLACE_QUEUED_ANIMATIONS);
         callout_settings.SetTransitionDuration(
@@ skipping 10 matching lines @@
 
 void PanelLayoutManager::OnKeyboardBoundsChanging(
     const gfx::Rect& keyboard_bounds) {
   // This bounds change will have caused a change to the Shelf which does not
   // propogate automatically to this class, so manually recalculate bounds.
   OnWindowResized();
 }
 
 }  // namespace internal
 }  // namespace ash