Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/docked_panel_strip.h

Index: chrome/browser/ui/panels/docked_panel_strip.h
diff --git a/chrome/browser/ui/panels/docked_panel_strip.h b/chrome/browser/ui/panels/docked_panel_strip.h
index 2fb002943a84d77ae1a730dd4bf1c3e73b0a1e1a..12467a30e9a149a6fb9f176ae506c57fe6f897b3 100644
--- a/chrome/browser/ui/panels/docked_panel_strip.h
+++ b/chrome/browser/ui/panels/docked_panel_strip.h
@@ -53,10 +53,17 @@ class DockedPanelStrip : public PanelStrip,
   virtual void MinimizePanel(Panel* panel) OVERRIDE;
   virtual void RestorePanel(Panel* panel) OVERRIDE;
   virtual bool CanShowPanelAsActive(const Panel* panel) const OVERRIDE;
+  virtual void SavePanelPlacement(Panel* panel) OVERRIDE;
+  virtual void LoadSavedPanelPlacement() OVERRIDE;
+  virtual void DiscardSavedPanelPlacement() OVERRIDE;
   virtual bool CanDragPanel(const Panel* panel) const OVERRIDE;
-  virtual void StartDraggingPanel(Panel* panel) OVERRIDE;
-  virtual void DragPanel(Panel* panel, int delta_x, int delta_y) OVERRIDE;
-  virtual void EndDraggingPanel(Panel* panel, bool cancelled) OVERRIDE;
+  virtual void StartDraggingPanelLocally(Panel* panel) OVERRIDE;
+  virtual void DragPanelLocally(Panel* panel,
+                                int delta_x,
+                                int delta_y) OVERRIDE;
+  virtual void EndDraggingPanelLocally(Panel* panel, bool cancelled) OVERRIDE;
+  virtual void AddDraggingPanel(Panel* panel,
+                                const gfx::Point& position) OVERRIDE;
 
   // Invoked when a panel's expansion state changes.
   void OnPanelExpansionStateChanged(Panel* panel);
@@ -104,9 +111,27 @@ class DockedPanelStrip : public PanelStrip,
     BRING_DOWN
   };
 
+  struct PanelPlacement {
+    Panel* panel;
+    // When |panel| is restored, it will be bring back before

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

The wording here is confusing to me. How about:

Remember the panel to the left, if any, for use when restoring the position of
the panel being dragged. Will be updated if the panel to the left is closed.

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

Done.

+    // |panel_to_place_before_|.
+    Panel* panel_to_place_before_;
+
+    PanelPlacement() : panel(NULL) { }
+  };
+
   // Overridden from PanelMouseWatcherObserver:
   virtual void OnMouseMove(const gfx::Point& mouse_position) OVERRIDE;
 
+  // Inserts |panel| to the collection at |position|.
+  // Returns the iterator that points to the newly inserted panel.
+  void InsertPanelToCollection(Panel* panel, Panels::iterator position);

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

Doesn't return anything. This sounds like a wrapper for list::insert?

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

Removed. We now don't need a wrapper. Instead, I introduced OnPanelAdded in
order to set common panel properties.

+
+  // Ensures that there is sufficient space in the strip to add a panel with
+  // the specified width. We might need to bump panels in the strip to make
+  // room for this panel.
+  void EnsureAvailableSpace(int width);
+
   // Keep track of the minimized panels to control mouse watching.
   void IncrementMinimizedPanels();
   void DecrementMinimizedPanels();
@@ -154,10 +179,6 @@ class DockedPanelStrip : public PanelStrip,
   // resides.
   Panels::iterator dragging_panel_current_iterator_;
 
-  // Referring to original position in |panels_| where the dragging panel
-  // resides.
-  Panels::iterator dragging_panel_original_iterator_;
-
   // Delayed transitions support. Sometimes transitions between minimized and
   // title-only states are delayed, for better usability with Taskbars/Docks.
   TitlebarAction delayed_titlebar_action_;
@@ -165,6 +186,9 @@ class DockedPanelStrip : public PanelStrip,
   // Owned by MessageLoop after posting.
   base::WeakPtrFactory<DockedPanelStrip> titlebar_action_factory_;
 
+  // Used to save the placement information for a panel.
+  PanelPlacement saved_panel_placement_;
+
   static const int kPanelsHorizontalSpacing = 4;
 
   // Absolute minimum width and height for panels, including non-client area.