Dragging panels near screen edge

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/launcher/launcher.h"
 #include "ash/screen_ash.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_types.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
+#include "ash/shell_window_ids.h"
 #include "ash/wm/frame_painter.h"
 #include "ash/wm/property_util.h"
 #include "ash/wm/window_animations.h"
+#include "ash/wm/window_properties.h"
 #include "ash/wm/window_util.h"
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/focus_manager.h"
@@ skipping 292 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // PanelLayoutManager, aura::LayoutManager implementation:
 void PanelLayoutManager::OnWindowResized() {
   Relayout();
 }
 
 void PanelLayoutManager::OnWindowAddedToLayout(aura::Window* child) {
   if (child->type() == aura::client::WINDOW_TYPE_POPUP)
     return;
+  if (!child->GetProperty(kPanelAttachedKey)) {
+    // This should only happen when a window is added to panel container as a
+    // result of bounds change from within the application during a drag.
+    // If so we have already stopped the drag and should reparent the panel
+    // back to appropriate container and ignore it.
+    // TODO(varkha): Updating bounds during a drag can cause problems and a more
+    // general solution is needed. See http://crbug.com/251813 .
+    child->SetDefaultParentByRootWindow(

[flackr, 2013/06/21 01:14:48]

It makes me uncomfortable that this could cause an infinite recursion if the
default parent was for some reason the panel container. You should probably
guard against that similar to how Relayout prevents infinite recursion.

[varkha, 2013/06/21 01:27:08]

Done. Cannot really happen with our current logic that depends on the same
variable but I am all for additional safeguards.

+        child->GetRootWindow(),
+        child->GetRootWindow()->GetBoundsInScreen());
+    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);
     panel_info.slide_in = true;
   }
   panel_windows_.push_back(panel_info);
@@ skipping 483 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