Refactor intra-strip panel drags by introducing PanelDragController.

chrome/browser/ui/panels/docked_panel_strip.cc

Index: chrome/browser/ui/panels/docked_panel_strip.cc
diff --git a/chrome/browser/ui/panels/docked_panel_strip.cc b/chrome/browser/ui/panels/docked_panel_strip.cc
index 40fbb2599e92b3b74cc5e7630a17c0b283e1fa67..9e3fcbea43f0acb8f41970b892203ae360b0c396 100644
--- a/chrome/browser/ui/panels/docked_panel_strip.cc
+++ b/chrome/browser/ui/panels/docked_panel_strip.cc
@@ -183,7 +183,6 @@ void DockedPanelStrip::AddPanel(Panel* panel) {
 
   // Set panel properties for this strip.
   panel->SetAppIconVisibility(true);
-  panel->set_draggable(!panel->has_temporary_layout());
   panel->ApplyVisualStyleForStrip();
 
   if (panel->has_temporary_layout())
@@ -252,7 +251,14 @@ bool DockedPanelStrip::DoRemove(Panel* panel) {
   return true;
 }
 
-void DockedPanelStrip::StartDragging(Panel* panel) {
+bool DockedPanelStrip::CanDragPanel(Panel* panel) const {
+  // Only the panels having temporary layout can't be dragged.
+  return !panel->has_temporary_layout();
+}
+
+void DockedPanelStrip::StartDraggingPanel(Panel* panel) {
+  DCHECK(!dragging_panel_);
+
   dragging_panel_iterator_ = find(panels_.begin(), panels_.end(), panel);
   DCHECK(dragging_panel_iterator_ != panels_.end());
 
@@ -261,7 +267,7 @@ void DockedPanelStrip::StartDragging(Panel* panel) {
   dragging_panel_original_x_ = dragging_panel_bounds_.x();
 }
 
-void DockedPanelStrip::Drag(int delta_x) {
+void DockedPanelStrip::DragPanel(int delta_x, int delta_y) {
   DCHECK(dragging_panel_);
 
   if (!delta_x)
@@ -356,11 +362,11 @@ void DockedPanelStrip::DragRight() {
   dragging_panel_bounds_.set_x(current_panel_left_boundary);
 }
 
-void DockedPanelStrip::EndDragging(bool cancelled) {
+void DockedPanelStrip::EndDraggingPanel(bool cancelled) {
   DCHECK(dragging_panel_);
 
   if (cancelled)
-    Drag(dragging_panel_original_x_ - dragging_panel_->GetBounds().x());
+    DragPanel(dragging_panel_original_x_ - dragging_panel_->GetBounds().x(), 0);
   else
     dragging_panel_->SetPanelBounds(dragging_panel_bounds_);