Temporarily remember the primary root window while replacing the display.

ash/display/display_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 "ash/display/display_controller.h"
 
 #include <algorithm>
 
 #include "ash/ash_switches.h"
 #include "ash/display/display_manager.h"
@@ skipping 143 matching lines @@
 
 // static
 void DisplayLayout::RegisterJSONConverter(
     base::JSONValueConverter<DisplayLayout>* converter) {
   converter->RegisterCustomField<Position>(
       "position", &DisplayLayout::position, &GetPositionFromString);
   converter->RegisterIntField("offset", &DisplayLayout::offset);
 }
 
 DisplayController::DisplayController()
-    : desired_primary_display_id_(gfx::Display::kInvalidDisplayID) {
+    : desired_primary_display_id_(gfx::Display::kInvalidDisplayID),
+      primary_root_window_for_replace_(NULL) {
   // Reset primary display to make sure that tests don't use
   // stale display info from previous tests.
   primary_display_id = gfx::Display::kInvalidDisplayID;
   delete primary_display_for_shutdown;
   primary_display_for_shutdown = NULL;
   num_displays_for_shutdown = -1;
 
   Shell::GetScreen()->AddObserver(this);
 }
 
@@ skipping 285 matching lines @@
       display_manager->GetDisplayAt(1) : display_manager->GetDisplayAt(0);
 }
 
 void DisplayController::OnDisplayBoundsChanged(const gfx::Display& display) {
   NotifyDisplayConfigurationChanging();
   UpdateDisplayBoundsForLayout();
   root_windows_[display.id()]->SetHostBounds(display.bounds_in_pixel());
 }
 
 void DisplayController::OnDisplayAdded(const gfx::Display& display) {
-  DCHECK(!root_windows_.empty());
   NotifyDisplayConfigurationChanging();
-  aura::RootWindow* root = AddRootWindowForDisplay(display);
-  UpdateDisplayBoundsForLayout();
-  if (desired_primary_display_id_ == display.id())
-    SetPrimaryDisplay(display);
-
-  Shell::GetInstance()->InitRootWindowForSecondaryDisplay(root);
+  if (primary_root_window_for_replace_) {
+    DCHECK(root_windows_.empty());
+    primary_display_id = display.id();
+    root_windows_[display.id()] = primary_root_window_for_replace_;
+    primary_root_window_for_replace_->SetProperty(
+        internal::kDisplayIdKey, display.id());
+    primary_root_window_for_replace_ = NULL;
+    UpdateDisplayBoundsForLayout();
+  } else {
+    DCHECK(!root_windows_.empty());
+    aura::RootWindow* root = AddRootWindowForDisplay(display);
+    UpdateDisplayBoundsForLayout();
+    if (desired_primary_display_id_ == display.id())
+      SetPrimaryDisplay(display);
+    Shell::GetInstance()->InitRootWindowForSecondaryDisplay(root);
+  }
 }
 
 void DisplayController::OnDisplayRemoved(const gfx::Display& display) {
   aura::RootWindow* root_to_delete = root_windows_[display.id()];
   DCHECK(root_to_delete) << display.ToString();
   NotifyDisplayConfigurationChanging();
 
   // Display for root window will be deleted when the Primary RootWindow
   // is deleted by the Shell.
   root_windows_.erase(display.id());
 
   // When the primary root window's display is removed, move the primary
   // root to the other display.
   if (primary_display_id == display.id()) {
+    // Temporarily store the primary root window in
+    // |primary_root_window_for_replace_| when replacing the display.
+    if (root_windows_.size() == 0) {
+      primary_display_id = gfx::Display::kInvalidDisplayID;
+      primary_root_window_for_replace_ = root_to_delete;
+      return;
+    }
     DCHECK_EQ(1U, root_windows_.size());
     primary_display_id = GetSecondaryDisplay()->id();
     aura::RootWindow* primary_root = root_to_delete;
 
     // Delete the other root instead.
     root_to_delete = root_windows_[primary_display_id];
     root_to_delete->SetProperty(internal::kDisplayIdKey, display.id());
 
     // Setup primary root.
     root_windows_[primary_display_id] = primary_root;
@@ skipping 74 matching lines @@
   secondary_display->set_bounds(
       gfx::Rect(new_secondary_origin, secondary_bounds.size()));
   secondary_display->UpdateWorkAreaFromInsets(insets);
 }
 
 void DisplayController::NotifyDisplayConfigurationChanging() {
   FOR_EACH_OBSERVER(Observer, observers_, OnDisplayConfigurationChanging());
 }
 
 }  // namespace ash