Attach panel while dragging to bring it in front of other panels.

ash/wm/panels/panel_window_resizer.cc

Index: ash/wm/panels/panel_window_resizer.cc
diff --git a/ash/wm/panels/panel_window_resizer.cc b/ash/wm/panels/panel_window_resizer.cc
index e306f29411bcc3ba85c4bc4ef58639947c21a03c..a35288d4abd5eef0646c7bb08270d1906c488e21 100644
--- a/ash/wm/panels/panel_window_resizer.cc
+++ b/ash/wm/panels/panel_window_resizer.cc
@@ -12,7 +12,9 @@
 #include "ash/shell_window_ids.h"
 #include "ash/wm/panels/panel_layout_manager.h"
 #include "ash/wm/property_util.h"
+#include "ash/wm/toplevel_window_event_handler.h"
 #include "ash/wm/window_properties.h"
+#include "ash/wm/window_resizer_owner.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
@@ -35,11 +37,12 @@ PanelWindowResizer::~PanelWindowResizer() {
 
 // static
 PanelWindowResizer*
-PanelWindowResizer::Create(aura::Window* window,
-                             const gfx::Point& location,
-                             int window_component) {
+PanelWindowResizer::Create(WindowResizerOwner* owner,
+                           aura::Window* window,
+                           const gfx::Point& location,
+                           int window_component) {
   Details details(window, location, window_component);
-  return details.is_resizable ? new PanelWindowResizer(details) : NULL;
+  return details.is_resizable ? new PanelWindowResizer(owner, details) : NULL;
 }
 
 void PanelWindowResizer::Drag(const gfx::Point& location, int event_flags) {
@@ -57,7 +60,8 @@ void PanelWindowResizer::Drag(const gfx::Point& location, int event_flags) {
 }
 
 void PanelWindowResizer::CompleteDrag(int event_flags) {
-  if (should_attach_ != was_attached_) {
+  if (details_.window->GetProperty(internal::kPanelAttachedKey) !=
+      should_attach_) {
     details_.window->SetProperty(internal::kPanelAttachedKey, should_attach_);
     details_.window->SetDefaultParentByRootWindow(
             details_.window->GetRootWindow(),
@@ -81,8 +85,10 @@ aura::Window* PanelWindowResizer::GetTarget() {
   return details_.window;
 }
 
-PanelWindowResizer::PanelWindowResizer(const Details& details)
-    : details_(details),
+PanelWindowResizer::PanelWindowResizer(WindowResizerOwner* owner,
+                                       const Details& details)
+    : owner_(owner),
+      details_(details),
       panel_container_(NULL),
       panel_layout_manager_(NULL),
       did_move_or_resize_(false),
@@ -140,13 +146,29 @@ bool PanelWindowResizer::AttachToLauncher(gfx::Rect* bounds) {
 }
 
 void PanelWindowResizer::StartedDragging() {
-  if (was_attached_)
-    panel_layout_manager_->StartDragging(details_.window);
+  // Tell the panel layout manager that we are dragging this panel before
+  // attaching it so that it does not get repositioned.
+  panel_layout_manager_->StartDragging(details_.window);
+  if (!was_attached_) {
+    // Attach the panel while dragging placing it in front of other panels.
+    details_.window->SetProperty(internal::kPanelAttachedKey, true);
+    details_.window->SetDefaultParentByRootWindow(
+            details_.window->GetRootWindow(),
+            details_.window->bounds());
+
+    if (owner_) {
+      ash::internal::RootWindowController* root_window_controller =
+          GetRootWindowController(details_.window->GetRootWindow());
+      WindowResizerOwner* new_owner =
+          root_window_controller->panel_container_handler();
+      owner_->PassResizer(new_owner);
+      owner_ = new_owner;
+    }
+  }
 }
 
 void PanelWindowResizer::FinishDragging() {
-  if (was_attached_)
-    panel_layout_manager_->FinishDragging();
+  panel_layout_manager_->FinishDragging();
 }
 
 }  // namespace aura