Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/panel_strip.h

Index: chrome/browser/ui/panels/panel_strip.h
diff --git a/chrome/browser/ui/panels/panel_strip.h b/chrome/browser/ui/panels/panel_strip.h
index 7b0bced6fc2a6b29013fbc85f8db791ffa6d87dd..290c7a23bcb4cee9a9fdea882cc49a5b139bdd48 100644
--- a/chrome/browser/ui/panels/panel_strip.h
+++ b/chrome/browser/ui/panels/panel_strip.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_UI_PANELS_PANEL_STRIP_H_
 #pragma once
 
+#include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 
 class Panel;
@@ -65,15 +66,34 @@ class PanelStrip {
   // Returns true if |panel| can be shown as active.
   virtual bool CanShowPanelAsActive(const Panel* panel) const = 0;
 
+  // Saves/loads/discards the placement information of |panel|. This is useful
+  // int bringing back the dragging panel to its original positioning when the

[jennb, 2012/03/03 02:19:33]

typo: int

[jianli, 2012/03/07 19:14:31]

Done.

+  // drag is cancelled.
+  virtual void SavePanelPlacement(Panel* panel) = 0;
+  virtual void LoadSavedPanelPlacement() = 0;

[jennb, 2012/03/03 02:19:33]

RestorePanelToSavedPlacement()?

[jianli, 2012/03/07 19:14:31]

Done.

+  virtual void DiscardSavedPanelPlacement() = 0;

[jennb, 2012/03/03 02:19:33]

Please comment that drag controller will only call one of Load or Discard and
when.

[jianli, 2012/03/07 19:14:31]

Done.

+
   // Returns true if |panel| is draggable.
   virtual bool CanDragPanel(const Panel* panel) const = 0;
 
-  // Drags |panel| in the bounds of this strip.
-  virtual void StartDraggingPanel(Panel* panel) = 0;
-  // |delta_x| and |delta_y| denotes how much the mouse has been moved since
-  // last time when DragPanel or StartDraggingPanel is called.
-  virtual void DragPanel(Panel* panel, int delta_x, int delta_y) = 0;
-  virtual void EndDraggingPanel(Panel* panel, bool cancelled) = 0;
+  // Starts dragging |panel| within this strip. The panel should already be
+  // in this strip.
+  virtual void StartDraggingPanelLocally(Panel* panel) = 0;

[jennb, 2012/03/03 02:19:33]

s/Locally/WithinStrip or InStrip

Locally might be too vague.

[jianli, 2012/03/07 19:14:31]

Done.

+
+  // Drags |panel| within this strip.
+  // |delta_x| and |delta_y| represents the offset from the last mouse location
+  // when StartDraggingPanelLocally or DragPanelLocally is called.
+  virtual void DragPanelLocally(Panel* panel, int delta_x, int delta_y) = 0;
+
+  // Ends dragging |panel| within this strip.
+  // If |cancelled| is false, |panel| will be positioned to its finalized
+  // position. Otherwise, |panel| will stay as it is.

[jennb, 2012/03/03 02:19:33]

Add explanation for how the drag is truly cancelled. E.g. Drag controller will
do it...

[jianli, 2012/03/07 19:14:31]

Done.

+  virtual void EndDraggingPanelLocally(Panel* panel, bool cancelled) = 0;
+
+  // Adds |panel| to the collection of panels, positions it at |position|
+  // in screen coordinates, and starts dragging it within this strip. This is
+  // invoked when the drag leaves other strip and enters this strip.
+  virtual void AddDraggingPanel(Panel* panel, const gfx::Point& position) = 0;
 
  protected:
   explicit PanelStrip(Type type);