ui: Cache the output of View::OnPaint when the View isn't invalid.

ui/views/view.h

 // 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.
 
 #ifndef UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
 #include "ui/accessibility/ax_enums.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/drop_target_event.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/layer_delegate.h"
 #include "ui/compositor/layer_owner.h"
+#include "ui/compositor/paint_cache.h"
 #include "ui/events/event.h"
 #include "ui/events/event_target.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/vector2d.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/view_targeter.h"
 #include "ui/views/views_export.h"
 
 #if defined(OS_WIN)
@@ skipping 1465 matching lines @@
   bool snap_layer_to_pixel_boundary_;
 
   // Painting ------------------------------------------------------------------
 
   // Background
   scoped_ptr<Background> background_;
 
   // Border.
   scoped_ptr<Border> border_;
 
+  // Cached output of painting to be reused in future frames until invalidated.
+  ui::PaintCache paint_cache_;
+
   // RTL painting --------------------------------------------------------------
 
   // Indicates whether or not the gfx::Canvas object passed to View::Paint()
   // is going to be flipped horizontally (using the appropriate transform) on
   // right-to-left locales for this View.
   bool flip_canvas_on_paint_for_rtl_ui_;
 
   // Accelerated painting ------------------------------------------------------
 
   bool paint_to_layer_;
@@ skipping 42 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_