Refactor intra-strip panel drags by introducing PanelDragController.

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 7cd7f875c4d119ae31ccba5e62764a2890eaada4..a09b6a93deb30b4670ae6e9d9d5601f0937a18c4 100644
--- a/chrome/browser/ui/panels/panel_strip.h
+++ b/chrome/browser/ui/panels/panel_strip.h
@@ -62,6 +62,16 @@ class PanelStrip {
   virtual void MinimizePanel(Panel* panel) = 0;
   virtual void RestorePanel(Panel* panel) = 0;
 
+  // Returns true if |panel| is draggable.
+  virtual bool CanDragPanel(Panel* panel) const = 0;
+
+  // Drags |panel| in the bounds of this strip.
+  virtual void StartDraggingPanel(Panel* panel) = 0;
+  // |delta_x| and |delta_y| are the offset from the last mouse position when
+  // DragPanel or StartDraggingPanel is called.

[jennb, 2012/02/16 22:31:00]

Not sure I understand the comment because there's no mouse position passed to
StartDraggingPanel() nor DragPanel().

[jianli, 2012/02/16 23:05:52]

We only care about how much the mouse has been moved since last time DragPanel
or StartDraggingPanel is called. The underlying code might choose to apply or
not apply these delta values to the origin of the panel being dragged. I've
updated the comment to make it clearer.

+  virtual void DragPanel(int delta_x, int delta_y) = 0;
+  virtual void EndDraggingPanel(bool cancelled) = 0;
+
  protected:
   explicit PanelStrip(Type type);
   virtual ~PanelStrip();