Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/panel_drag_controller.h

Index: chrome/browser/ui/panels/panel_drag_controller.h
diff --git a/chrome/browser/ui/panels/panel_drag_controller.h b/chrome/browser/ui/panels/panel_drag_controller.h
index df944a586e685d5958d7d40e9d3f160d675f9d53..b41b73bcfe2a8af98834565326a93864e6f44e84 100644
--- a/chrome/browser/ui/panels/panel_drag_controller.h
+++ b/chrome/browser/ui/panels/panel_drag_controller.h
@@ -11,12 +11,14 @@
 #include "ui/gfx/point.h"
 
 class Panel;
+class PanelManager;
+class PanelStrip;
 
 // Responsible for handling drags initiated for all panels, including both
 // intra-strip and inter-strip drags.
 class PanelDragController {
  public:
-  PanelDragController();
+  explicit PanelDragController(PanelManager* panel_manager);
   ~PanelDragController();
 
   // Drags the given panel.
@@ -31,23 +33,53 @@ class PanelDragController {
   bool IsDragging() const { return dragging_panel_ != NULL; }
 
   Panel* dragging_panel() const { return dragging_panel_; }
-  gfx::Point dragging_panel_original_position() const {
-    return dragging_panel_original_position_;
+
+#ifdef UNIT_TEST
+  static int GetDetachDockedPanelThreshold() {
+    return kDetachDockedPanelThreshold;
+  }
+
+  static int GetDockDetachedPanelThreshold() {
+    return kDockDetachedPanelThreshold;
   }
+#endif
 
  private:
+  // Used to figure out if the panel can be dragged to other strip.

[jennb, 2012/03/08 23:41:09]

Comment what the params and return values mean.

[jianli, 2012/03/09 21:48:58]

Done.

+  PanelStrip* ComputeDragTagetStrip(

[jennb, 2012/03/08 23:41:09]

typo: Taget

[jianli, 2012/03/09 21:48:58]

Done.

+      const gfx::Point& mouse_location, gfx::Point* new_panel_position) const;
+  bool CanDragToDockedStrip(
+      const gfx::Point& mouse_location, gfx::Point* new_panel_position) const;
+  bool CanDragToDetachedStrip(
+      const gfx::Point& mouse_location, gfx::Point* new_panel_position) const;
+
+  int GetOffsetToDockedAreaBottom(

[jennb, 2012/03/08 23:41:09]

Needs comment. Unclear what this is.

[jianli, 2012/03/09 21:48:58]

Removed since it is not needed now.

+      const gfx::Point& target_panel_position) const;
+
+  PanelManager* panel_manager_;  // Weak, owns us.
+
   // Panel currently being dragged.
   Panel* dragging_panel_;
 
-  // Original position, in screen coordinate system, of the panel being dragged.
-  // This is used to get back to the original position when we cancel the
-  // dragging.
-  gfx::Point dragging_panel_original_position_;
+  // The original panel strip when the drag is started.
+  PanelStrip* dragging_panel_original_strip_;
 
   // The mouse location, in screen coordinates, when StartDragging or Drag was
   // pveviously called.
   gfx::Point last_mouse_location_;
 
+  // The offset from mouse location to the panel position when the drag
+  // starts.
+  gfx::Point offset_from_mouse_location_on_drag_start_;

[jennb, 2012/03/08 23:41:09]

This is a delta of some sort? I don't understand the comment to know what it's
measuring.

[jianli, 2012/03/09 21:48:58]

Comment updated.

+
+  // The minimum distance that the docked panel gets dragged up in order to
+  // make it free-floating.
+  static const int kDetachDockedPanelThreshold;
+
+  // Indicates how close the bottom of the detached panel is to the bottom of
+  // the docked area such that the detached panel becomes docked.
+  static const int kDockDetachedPanelThreshold;
+
   DISALLOW_COPY_AND_ASSIGN(PanelDragController);
 };