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

chrome/browser/ui/panels/panel_drag_controller.cc

Index: chrome/browser/ui/panels/panel_drag_controller.cc
diff --git a/chrome/browser/ui/panels/panel_drag_controller.cc b/chrome/browser/ui/panels/panel_drag_controller.cc
index 2a21cd28b7ffdf9af6b959ce845b07a30c172a51..7cd099053250f7f231d2d5a9c357245f66f0f825 100644
--- a/chrome/browser/ui/panels/panel_drag_controller.cc
+++ b/chrome/browser/ui/panels/panel_drag_controller.cc
@@ -15,20 +15,28 @@ PanelDragController::PanelDragController()
 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) {