Change panel drag related methods to use mouse location in screen coordinates.

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() {
 }
 
-void PanelDragController::StartDragging(Panel* panel) {
+void PanelDragController::StartDragging(Panel* panel,
+                                        const gfx::Point& mouse_location) {
   DCHECK(!dragging_panel_);
   DCHECK(panel->draggable());
 
+  last_mouse_location_ = mouse_location;
+
   dragging_panel_ = panel;
   dragging_panel_original_position_ = panel->GetBounds().origin();
 
   dragging_panel_->panel_strip()->StartDraggingPanel(panel);
 }
 
-void PanelDragController::Drag(int delta_x, int delta_y) {
+void PanelDragController::Drag(const gfx::Point& mouse_location) {
   DCHECK(dragging_panel_);
 
-  dragging_panel_->panel_strip()->DragPanel(dragging_panel_, delta_x, delta_y);
+  dragging_panel_->panel_strip()->DragPanel(
+        dragging_panel_,
+        mouse_location.x() - last_mouse_location_.x(),
+        mouse_location.y() - last_mouse_location_.y());
+
+  last_mouse_location_ = mouse_location;
 }
 
 void PanelDragController::EndDragging(bool cancelled) {
   DCHECK(dragging_panel_);
 
   // The code in PanelStrip::EndDraggingPanel might call DragController to find
   // out if the drag has ended. So we need to reset |dragging_panel_| to reflect
   // this.
   Panel* panel = dragging_panel_;
   dragging_panel_ = NULL;
   panel->panel_strip()->EndDraggingPanel(panel, cancelled);
 }
 
 void PanelDragController::OnPanelClosed(Panel* panel) {
   if (!dragging_panel_)
     return;
 
   // If the dragging panel is closed, abort the drag.
   if (dragging_panel_ == panel)
     EndDragging(false);
 }