wm: Use CursorManager::GetDisplay for display id only

The Display object returned by CursorManager::GetDisplay can be stale,
particularly if you change display resolution. So it shall be used only
for the display id, which can be used to get a current Display object.

Test: manual
Bug: 995413, b/149273461
Change-Id: I7624ec5f09aefd55703412bb053d5204461eca43
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2088237Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746971}

ash/wm/drag_window_resizer.cc

@@ -128,15 +128,19 @@ void DragWindowResizer::EndDragImpl() {
   if (details().source == wm::WINDOW_MOVE_SOURCE_TOUCH)
     return;
   aura::Window* root_window = GetTarget()->GetRootWindow();
-  const display::Display dst_display =
-      Shell::Get()->cursor_manager()->GetDisplay();
-  if (dst_display.id() ==
-      display::Screen::GetScreen()->GetDisplayNearestWindow(root_window).id()) {
+  // The |Display| object returned by |CursorManager::GetDisplay| may be stale,
+  // but will have the correct id.
+  // TODO(oshima): Change the API so |GetDisplay| just returns a display id.
+  const int64_t dst_display_id =
+      Shell::Get()->cursor_manager()->GetDisplay().id();
+  display::Screen* screen = display::Screen::GetScreen();
+  if (dst_display_id == screen->GetDisplayNearestWindow(root_window).id())
     return;
-  }
 
   // Adjust the size and position so that it doesn't exceed the size of work
   // area.
+  display::Display dst_display;
+  screen->GetDisplayWithDisplayId(dst_display_id, &dst_display);
   const gfx::Size& size = dst_display.work_area().size();
   gfx::Rect bounds = GetTarget()->bounds();
   if (bounds.width() > size.width()) {

ash/wm/overview/overview_window_drag_controller.cc

@@ -635,20 +635,13 @@ aura::Window* OverviewWindowDragController::GetRootWindowBeingDraggedIn()
                    Shell::Get()->cursor_manager()->GetDisplay().id());
 }
 
-gfx::Rect OverviewWindowDragController::GetWorkAreaOfDisplayBeingDraggedIn()
-    const {
-  return is_touch_dragging_
-             ? screen_util::
-                   GetDisplayWorkAreaBoundsInScreenForActiveDeskContainer(
-                       item_->root_window())
-             : Shell::Get()->cursor_manager()->GetDisplay().work_area();
-}
-
 SplitViewController::SnapPosition OverviewWindowDragController::GetSnapPosition(
     const gfx::PointF& location_in_screen) const {
   DCHECK(item_);
   DCHECK(should_allow_split_view_);
-  gfx::Rect area = GetWorkAreaOfDisplayBeingDraggedIn();
+  gfx::Rect area =
+      screen_util::GetDisplayWorkAreaBoundsInScreenForActiveDeskContainer(
+          GetRootWindowBeingDraggedIn());
 
   // If split view mode is active at the moment, and dragging an overview window
   // to snap it to a position that already has a snapped window in place, we

ash/wm/overview/overview_window_drag_controller.h

@@ -106,7 +106,6 @@ class ASH_EXPORT OverviewWindowDragController {
       const gfx::PointF& location_in_screen);
 
   aura::Window* GetRootWindowBeingDraggedIn() const;
-  gfx::Rect GetWorkAreaOfDisplayBeingDraggedIn() const;
 
   SplitViewController::SnapPosition GetSnapPosition(
       const gfx::PointF& location_in_screen) const;

ash/wm/workspace/workspace_window_resizer.cc

@@ -1032,11 +1032,19 @@ void WorkspaceWindowResizer::UpdateSnapPhantomWindow(
   if (!did_move_or_resize_ || details().window_component != HTCAPTION)
     return;
 
-  const display::Display& display =
-      details().source == ::wm::WINDOW_MOVE_SOURCE_TOUCH
-          ? display::Screen::GetScreen()->GetDisplayNearestWindow(GetTarget())
-          : Shell::Get()->cursor_manager()->GetDisplay();
+  display::Screen* screen = display::Screen::GetScreen();
+  display::Display display;
+  if (details().source == ::wm::WINDOW_MOVE_SOURCE_TOUCH) {
+    display = screen->GetDisplayNearestWindow(GetTarget());
+  } else {
+    // The |Display| object returned by |CursorManager::GetDisplay| may be
+    // stale, but will have the correct id.
+    // TODO(oshima): Change the API so |GetDisplay| just returns a display id.
+    screen->GetDisplayWithDisplayId(
+        Shell::Get()->cursor_manager()->GetDisplay().id(), &display);
+  }
   SnapType last_type = snap_type_;
+  DCHECK(display.is_valid());
   snap_type_ = GetSnapType(display, location_in_screen);
   if (snap_type_ == SNAP_NONE || snap_type_ != last_type) {
     snap_phantom_window_controller_.reset();