Refactor intra-strip panel drags by introducing PanelDragController.

chrome/browser/ui/panels/detached_panel_strip.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/ui/panels/detached_panel_strip.h"
 
 #include <algorithm>
 #include "base/logging.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
 
 DetachedPanelStrip::DetachedPanelStrip(PanelManager* panel_manager)
     : PanelStrip(PanelStrip::DETACHED),
-      panel_manager_(panel_manager) {
+      panel_manager_(panel_manager),
+      dragging_panel_(NULL) {
 }
 
 DetachedPanelStrip::~DetachedPanelStrip() {
   DCHECK(panels_.empty());
 }
 
 void DetachedPanelStrip::SetDisplayArea(const gfx::Rect& display_area) {
   if (display_area_ == display_area)
     return;
   display_area_ = display_area;
@@ skipping 48 matching lines @@
 void DetachedPanelStrip::MinimizePanel(Panel* panel) {
   DCHECK_EQ(this, panel->panel_strip());
   NOTIMPLEMENTED();
 }
 
 void DetachedPanelStrip::RestorePanel(Panel* panel) {
   DCHECK_EQ(this, panel->panel_strip());
   NOTIMPLEMENTED();
 }
 
+bool DetachedPanelStrip::CanDragPanel(Panel* panel) const {
+  // All detached panels are draggable.
+  return true;
+}
+
+void DetachedPanelStrip::StartDraggingPanel(Panel* panel) {
+  DCHECK(!dragging_panel_);
+
+  dragging_panel_ = panel;
+  dragging_panel_original_position_ = panel->GetBounds().origin();
+}
+
+void DetachedPanelStrip::DragPanel(int delta_x, int delta_y) {
+  DCHECK(dragging_panel_);
+
+  gfx::Rect new_bounds(dragging_panel_->GetBounds());
+  new_bounds.Offset(delta_x, delta_y);
+  dragging_panel_->SetPanelBounds(new_bounds);
+}
+
+void DetachedPanelStrip::EndDraggingPanel(bool cancelled) {
+  DCHECK(dragging_panel_);
+
+  if (cancelled) {
+    gfx::Rect new_bounds(dragging_panel_->GetBounds());
+    new_bounds.set_origin(dragging_panel_original_position_);
+    dragging_panel_->SetPanelBounds(new_bounds);
+  }
+
+  dragging_panel_ = NULL;
+}