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

ui/compositor/paint_cache.h

Index: ui/compositor/paint_cache.h
diff --git a/ui/compositor/paint_cache.h b/ui/compositor/paint_cache.h
deleted file mode 100644
index 599a8ac355340aeaa9b4c92a5e48cf374fd5ec9f..0000000000000000000000000000000000000000
--- a/ui/compositor/paint_cache.h
+++ /dev/null
@@ -1,45 +0,0 @@
-// 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.
-
-#ifndef UI_COMPOSITOR_PAINT_CACHE_H_
-#define UI_COMPOSITOR_PAINT_CACHE_H_
-
-#include "base/memory/scoped_ptr.h"
-#include "ui/compositor/compositor_export.h"
-
-namespace cc {
-class DrawingDisplayItem;
-}
-
-namespace ui {
-class PaintContext;
-class PaintRecorder;
-
-// A class that holds the output of a PaintRecorder to be reused when the
-// object that created the PaintRecorder has not been changed/invalidated.
-class COMPOSITOR_EXPORT PaintCache {
- public:
-  PaintCache();
-  ~PaintCache();
-
-  // Returns true if the PaintCache was able to insert a previously-saved
-  // painting output into the PaintContext. If it returns false, the caller
-  // needs to do the work of painting, which can be stored into the PaintCache
-  // to be used next time.
-  bool UseCache(const PaintContext& context);
-
- private:
-  // Only PaintRecorder can modify these.
-  friend PaintRecorder;
-
-  void SetCache(scoped_ptr<cc::DrawingDisplayItem> item);
-
-  scoped_ptr<cc::DrawingDisplayItem> display_item_;
-
-  DISALLOW_COPY_AND_ASSIGN(PaintCache);
-};
-
-}  // namespace ui
-
-#endif  // UI_COMPOSITOR_PAINT_CACHE_H_