Use ScopedSetRasterScale to set overview mode window scale.

If this CL needs to be reverted for causing a graphical glitch or
performance issue in lacros, it can be effectively reverted easily (in
the case of a non-clean revert, or unsure of revert safety) by removing
the zaura_toplevel_send_configure_raster_scale call from
AuraToplevel::OnConfigure.

CL 8/? for go/lacros-tsr

See also go/lacros-tsr-scale-control for the reasoning behind this CL

Bug: 1278651
Test: CQ
Change-Id: I9ece8527b2097fe9e2076b21924ae718b369acbf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4229937
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Eliot Courtney <edcourtney@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1188170}

ash/BUILD.gn

@@ -2545,6 +2545,8 @@ component("ash") {
     "wm/pip/pip_window_resizer.h",
     "wm/raster_scale/raster_scale_controller.cc",
     "wm/raster_scale/raster_scale_controller.h",
+    "wm/raster_scale/raster_scale_layer_observer.cc",
+    "wm/raster_scale/raster_scale_layer_observer.h",
     "wm/resize_shadow.cc",
     "wm/resize_shadow.h",
     "wm/resize_shadow_controller.cc",

ash/wm/desks/desks_controller.cc

@@ -1762,6 +1762,11 @@ void DesksController::RemoveDeskInternal(const Desk* desk,
                                          DesksCreationRemovalSource source,
                                          DeskCloseType close_type,
                                          bool desk_switched) {
+  // Removing a desk can cause transient raster scale updates during overview
+  // mode, if desks are combined. Pause raster scale updates until windows are
+  // in their final state.
+  ScopedPauseRasterScaleUpdates scoped_pause;
+
   MaybeCommitPendingDeskRemoval();
 
   DCHECK(CanRemoveDesks());

ash/wm/overview/overview_controller.cc

@@ -20,6 +20,7 @@
 #include "ash/wm/overview/overview_item.h"
 #include "ash/wm/overview/overview_utils.h"
 #include "ash/wm/overview/overview_wallpaper_controller.h"
+#include "ash/wm/raster_scale/raster_scale_controller.h"
 #include "ash/wm/screen_pinning_controller.h"
 #include "ash/wm/snap_group/snap_group_controller.h"
 #include "ash/wm/splitview/split_view_controller.h"
@@ -296,6 +297,11 @@ OverviewController::GetWindowsListInOverviewGridsForTest() {
 }
 
 void OverviewController::ToggleOverview(OverviewEnterExitType type) {
+  // Pause raster scale updates while the overview is being toggled. This is to
+  // handle the case where a mirror view is deleted then recreated when
+  // cancelling an overview exit animation, for example.
+  ScopedPauseRasterScaleUpdates scoped_pause;
+
   // Hide the virtual keyboard as it obstructs the overview mode.
   // Don't need to hide if it's the a11y keyboard, as overview mode
   // can accept text input and it resizes correctly with the a11y keyboard.

ash/wm/overview/overview_item.cc

@@ -31,6 +31,7 @@
 #include "ash/wm/overview/overview_window_drag_controller.h"
 #include "ash/wm/overview/scoped_overview_animation_settings.h"
 #include "ash/wm/overview/scoped_overview_hide_windows.h"
+#include "ash/wm/raster_scale/raster_scale_controller.h"
 #include "ash/wm/splitview/split_view_constants.h"
 #include "ash/wm/splitview/split_view_utils.h"
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
@@ -340,6 +341,12 @@ gfx::RectF OverviewItem::GetWindowTargetBoundsWithInsets() const {
 
 void OverviewItem::SetBounds(const gfx::RectF& target_bounds,
                              OverviewAnimationType animation_type) {
+  // Pause raster scale updates during SetBounds. For example, if we perform an
+  // item spawned animation, we set the initial transform but immediately start
+  // an animation, so we don't want to trigger a raster scale update for the
+  // initial transform.
+  ScopedPauseRasterScaleUpdates scoped_pause;
+
   if (in_bounds_update_ ||
       !Shell::Get()->overview_controller()->InOverviewSession()) {
     return;