ash: Some code-cleanup around tray-resizing code.

ash/system/tray/system_tray.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/system/tray/system_tray.h"
 
 #include "ash/shell.h"
 #include "ash/shell/panel_window.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/audio/tray_volume.h"
@@ skipping 67 matching lines @@
     SkScalar radius = SkIntToScalar(kTrayRoundedBorderRadius);
     path.addRoundRect(gfx::RectToSkRect(bounds), radius, radius);
     canvas->DrawPath(path, paint);
   }
 
   int alpha_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayBackground);
 };
 
+// Container for all the items in the tray. The container auto-resizes the
+// widget when necessary.
+class SystemTrayContainer : public views::View {
+ public:
+  SystemTrayContainer() {}
+  virtual ~SystemTrayContainer() {}
+
+ private:
+  void UpdateWidgetSize() {
+    if (GetWidget())
+      GetWidget()->SetSize(GetWidget()->GetContentsView()->GetPreferredSize());
+  }
+
+  // Overridden from views::View.
+  virtual void ChildPreferredSizeChanged(views::View* child) {
+    views::View::ChildPreferredSizeChanged(child);
+    UpdateWidgetSize();
+  }
+
+  virtual void ChildVisibilityChanged(View* child) OVERRIDE {
+    views::View::ChildVisibilityChanged(child);
+    UpdateWidgetSize();
+  }
+
+  virtual void ViewHierarchyChanged(bool is_add,
+                                    View* parent,
+                                    View* child) OVERRIDE {
+    if (parent == this)
+      UpdateWidgetSize();
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(SystemTrayContainer);
+};
+
 // Observe the tray layer animation and update the anchor when it changes.
 // TODO(stevenjb): Observe or mirror the actual animation, not just the start
 // and end points.
 class SystemTrayLayerAnimationObserver : public ui::LayerAnimationObserver {
  public:
   explicit SystemTrayLayerAnimationObserver(SystemTray* host) : host_(host) {}
 
   virtual void OnLayerAnimationEnded(ui::LayerAnimationSequence* sequence) {
     host_->UpdateNotificationAnchor();
   }
@@ skipping 33 matching lines @@
       power_status_observer_(NULL),
       update_observer_(NULL),
       user_observer_(NULL),
       widget_(NULL),
       background_(new internal::SystemTrayBackground),
       should_show_launcher_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(hide_background_animator_(this,
           0, kTrayBackgroundAlpha)),
       ALLOW_THIS_IN_INITIALIZER_LIST(hover_background_animator_(this,
           0, kTrayBackgroundHoverAlpha - kTrayBackgroundAlpha)) {
-  tray_container_ = new views::View;
+  tray_container_ = new internal::SystemTrayContainer;
   tray_container_->SetLayoutManager(new views::BoxLayout(
       views::BoxLayout::kHorizontal, 0, 0, 0));
   tray_container_->set_background(background_);
   tray_container_->set_border(
       views::Border::CreateEmptyBorder(1, 1, 1, 1));
   set_border(views::Border::CreateEmptyBorder(0, 0,
         kPaddingFromBottomOfScreen, kPaddingFromRightEdgeOfScreen));
   set_notify_enter_exit_on_child(true);
   SetLayoutManager(new views::BoxLayout(views::BoxLayout::kVertical, 0, 0, 0));
   AddChildView(tray_container_);
@@ skipping 283 matching lines @@
     canvas->DrawFocusRect(tray_container_->bounds());
 }
 
 void SystemTray::UpdateBackground(int alpha) {
   background_->set_alpha(hide_background_animator_.alpha() +
                          hover_background_animator_.alpha());
   SchedulePaint();
 }
 
 }  // namespace ash