Refactor intra-strip panel drags by introducing PanelDragController.

chrome/browser/ui/panels/panel_drag_controller.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/panel_drag_controller.h"
+
+#include "base/logging.h"
+#include "chrome/browser/ui/panels/panel.h"
+#include "chrome/browser/ui/panels/panel_strip.h"
+
+PanelDragController::PanelDragController()
+    : dragging_panel_(NULL) {
+}
+
+PanelDragController::~PanelDragController() {
+}
+
+bool PanelDragController::CanDrag(Panel* panel) const {
+  return panel->panel_strip()->CanDragPanel(panel);
+}
+
+void PanelDragController::StartDragging(Panel* panel) {
+  DCHECK(!dragging_panel_);
+
+  dragging_panel_ = panel;
+  dragging_panel_->panel_strip()->StartDraggingPanel(panel);
+}
+
+void PanelDragController::Drag(int delta_x, int delta_y) {
+  DCHECK(dragging_panel_);
+
+  dragging_panel_->panel_strip()->DragPanel(delta_x, delta_y);
+}
+
+void PanelDragController::EndDragging(bool cancelled) {
+  DCHECK(dragging_panel_);
+
+  dragging_panel_->panel_strip()->EndDraggingPanel(cancelled);
+  dragging_panel_ = NULL;
+}