ash: Use PaintRecorder in CursorWindowDelegate

ash/display/cursor_window_controller.cc

 // Copyright 2014 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/cursor_window_controller.h"
 
 #include "ash/display/display_controller.h"
 #include "ash/display/mirror_window_controller.h"
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/cursor/cursors_aura.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/paint_context.h"
+#include "ui/compositor/paint_recorder.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_skia_operations.h"
 
 namespace ash {
 
 class CursorWindowDelegate : public aura::WindowDelegate {
  public:
   CursorWindowDelegate() : is_cursor_compositing_enabled_(false) {}
@@ skipping 12 matching lines @@
     return HTNOWHERE;
   }
   bool ShouldDescendIntoChildForEventHandling(
       aura::Window* child,
       const gfx::Point& location) override {
     return false;
   }
   bool CanFocus() override { return false; }
   void OnCaptureLost() override {}
   void OnPaint(const ui::PaintContext& context) override {
-    context.canvas()->DrawImageInt(cursor_image_, 0, 0);
+    // No need to cache the output here, the CursorWindow is not invalidated.
+    ui::PaintRecorder recorder(context);
+    recorder.canvas()->DrawImageInt(cursor_image_, 0, 0);
   }
   void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
   void OnWindowDestroying(aura::Window* window) override {}
   void OnWindowDestroyed(aura::Window* window) override {}
   void OnWindowTargetVisibilityChanged(bool visible) override {}
   bool HasHitTestMask() const override { return false; }
   void GetHitTestMask(gfx::Path* mask) const override {}
 
   // Sets cursor compositing mode on/off.
   void SetCursorCompositingEnabled(bool enabled) {
@@ skipping 207 matching lines @@
   if (!cursor_window_)
     return;
   bool visible = (visible_ && cursor_type_ != ui::kCursorNone);
   if (visible)
     cursor_window_->Show();
   else
     cursor_window_->Hide();
 }
 
 }  // namespace ash