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

ui/compositor/paint_cache.cc

-// Copyright 2015 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 "ui/compositor/paint_cache.h"
-
-#include "cc/resources/display_item_list.h"
-#include "cc/resources/drawing_display_item.h"
-#include "ui/compositor/paint_context.h"
-
-namespace ui {
-
-PaintCache::PaintCache() {
-}
-
-PaintCache::~PaintCache() {
-}
-
-bool PaintCache::UseCache(const PaintContext& context) {
-  if (!display_item_)
-    return false;
-  DCHECK(context.list_);
-  context.list_->AppendItem(display_item_->Clone());
-  return true;
-}
-
-void PaintCache::SetCache(scoped_ptr<cc::DrawingDisplayItem> item) {
-  display_item_ = item.Pass();
-}
-
-}  // namespace ui