Keep the window tree host until MoveWindowsTo() is finished.

Some handlers in MoveWindowsTo() can GetRootWindowForDisplayId().
This causes a crash because the removing gfx::Display is still
valid but the corresponding window tree host is already detached.

This CL delays the detaching, window tree host is still valid
during OnDisplayRemoved().

BUG=415222
R=oshima@chromium.org
TEST=the new test case covers

Review URL: https://codereview.chromium.org/1017533003

Cr-Commit-Position: refs/heads/master@{#321054}

1 files changed, 47 insertions, 0 deletions

diff --git a/ash/display/display_controller_unittest.cc b/ash/display/display_controller_unittest.cc
index a753d1b..6945fac2 100644
--- a/ash/display/display_controller_unittest.cc
+++ b/ash/display/display_controller_unittest.cc
@@ -29,6 +29,9 @@
 #include "ui/events/test/event_generator.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/screen.h"
+#include "ui/views/mouse_watcher.h"
+#include "ui/views/mouse_watcher_view_host.h"
+#include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 #include "ui/wm/public/activation_change_observer.h"
 #include "ui/wm/public/activation_client.h"
@@ -375,6 +378,17 @@ std::string GetXWindowName(aura::WindowTreeHost* host) {
 }
 #endif
 
+class TestMouseWatcherListener : public views::MouseWatcherListener {
+ public:
+  TestMouseWatcherListener() {}
+
+ private:
+  // views::MouseWatcherListener:
+  void MouseMovedOutOfHost() override {}
+
+  DISALLOW_COPY_AND_ASSIGN(TestMouseWatcherListener);
+};
+
 }  // namespace
 
 typedef test::AshTestBase DisplayControllerTest;
@@ -1460,4 +1474,37 @@ TEST_F(DisplayControllerTest,
   EXPECT_EQ(gfx::Display::ROTATE_90, test_api.GetCurrentCursorRotation());
 }
 
+// GetRootWindowForDisplayId() for removed gfx::Display during
+// OnDisplayRemoved() should not cause crash. See http://crbug.com/415222
+TEST_F(DisplayControllerTest,
+       GetRootWindowForDisplayIdDuringDisplayDisconnection) {
+  if (!SupportsMultipleDisplays())
+    return;
+
+  UpdateDisplay("300x300,200x200");
+  aura::Window* root2 =
+      Shell::GetInstance()->display_controller()->GetRootWindowForDisplayId(
+          ScreenUtil::GetSecondaryDisplay().id());
+  views::Widget* widget = views::Widget::CreateWindowWithContextAndBounds(
+      nullptr, root2, gfx::Rect(350, 0, 100, 100));
+  views::View* view = new views::View();
+  widget->GetContentsView()->AddChildView(view);
+  view->SetBounds(0, 0, 100, 100);
+  widget->Show();
+
+  TestMouseWatcherListener listener;
+  views::MouseWatcher watcher(
+      new views::MouseWatcherViewHost(view, gfx::Insets()), &listener);
+  watcher.Start();
+
+  ui::test::EventGenerator event_generator(
+      widget->GetNativeWindow()->GetRootWindow());
+  event_generator.MoveMouseToCenterOf(widget->GetNativeWindow());
+
+  UpdateDisplay("300x300");
+  watcher.Stop();
+
+  widget->CloseNow();
+}
+
 }  // namespace ash