Support dragging panels to stack and snap.

chrome/browser/ui/views/panels/panel_stack_view.h

Index: chrome/browser/ui/views/panels/panel_stack_view.h
diff --git a/chrome/browser/ui/views/panels/panel_stack_view.h b/chrome/browser/ui/views/panels/panel_stack_view.h
new file mode 100644
index 0000000000000000000000000000000000000000..e79dd20b7c4f84b601e300f23ab396fcd6cad4ed
--- /dev/null
+++ b/chrome/browser/ui/views/panels/panel_stack_view.h
@@ -0,0 +1,60 @@
+// Copyright (c) 2013 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.
+
+#ifndef CHROME_BROWSER_UI_VIEWS_PANELS_PANEL_STACK_VIEW_H_
+#define CHROME_BROWSER_UI_VIEWS_PANELS_PANEL_STACK_VIEW_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/ui/panels/native_panel_stack.h"
+#include "ui/views/widget/widget_delegate.h"
+#include "ui/views/widget/widget_observer.h"
+
+class StackedPanelCollection;
+
+// A native window that acts as the owner of all panels in the stack, in order
+// to make all panels appear as a single window on the taskbar or launcher.
+class PanelStackView : public NativePanelStack,
+                       public views::WidgetObserver,
+                       public views::WidgetDelegateView {
+ public:
+  explicit PanelStackView(
+      scoped_ptr<StackedPanelCollection> stacked_collection);
+  virtual ~PanelStackView();
+
+ protected:
+  // Overridden from NativePanelStack:
+  virtual void Close() OVERRIDE;
+  virtual void OnPanelAddedOrRemoved(Panel* panel) OVERRIDE;
+  virtual void SetBounds(const gfx::Rect& bounds) OVERRIDE;
+
+ private:
+  // Overridden from views::WidgetDelegate:
+  virtual string16 GetWindowTitle() const OVERRIDE;
+  virtual gfx::ImageSkia GetWindowAppIcon() OVERRIDE;
+  virtual gfx::ImageSkia GetWindowIcon() OVERRIDE;
+  virtual views::Widget* GetWidget() OVERRIDE;
+  virtual const views::Widget* GetWidget() const OVERRIDE;
+  virtual void DeleteDelegate() OVERRIDE;
+
+  // Overridden from views::WidgetObserver:
+  virtual void OnWidgetClosing(views::Widget* widget) OVERRIDE;
+
+  void EnsureInitialized();
+
+  // Updates the owner of the underlying window such that multiple panels
+  // stacked together could appear as a single window on the taskbar or
+  // launcher.
+  void UpdateWindowOwnerForTaskbarIconAppearance(Panel* panel);
+
+  scoped_ptr<StackedPanelCollection> stacked_collection_;
+
+  bool delay_initialized_;
+
+  views::Widget* window_;
+
+  DISALLOW_COPY_AND_ASSIGN(PanelStackView);
+};
+
+#endif  // CHROME_BROWSER_UI_VIEWS_PANELS_PANEL_STACK_VIEW_H_