Remove parts of //cc we aren't using

cc/resources/pixel_ref_map.h

-// 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 CC_RESOURCES_PIXEL_REF_MAP_H_
-#define CC_RESOURCES_PIXEL_REF_MAP_H_
-
-#include <utility>
-#include <vector>
-
-#include "base/containers/hash_tables.h"
-#include "base/lazy_instance.h"
-#include "base/memory/ref_counted.h"
-#include "cc/base/cc_export.h"
-#include "third_party/skia/include/core/SkPicture.h"
-#include "ui/gfx/geometry/rect.h"
-#include "ui/gfx/geometry/size.h"
-
-class SkPixelRef;
-
-namespace cc {
-
-class Picture;
-
-typedef std::pair<int, int> PixelRefMapKey;
-typedef std::vector<SkPixelRef*> PixelRefs;
-typedef base::hash_map<PixelRefMapKey, PixelRefs> PixelRefHashmap;
-
-// This class is used and owned by cc Picture class. It is used to gather pixel
-// refs which would happen after record. It takes in |cell_size| to decide how
-// big each grid cell should be.
-class CC_EXPORT PixelRefMap {
- public:
-  explicit PixelRefMap(const gfx::Size& cell_size);
-  ~PixelRefMap();
-  void GatherPixelRefsFromPicture(SkPicture* picture);
-
-  bool empty() const { return data_hash_map_.empty(); }
-
-  // This iterator imprecisely returns the set of pixel refs that are needed to
-  // raster this layer rect from this picture.  Internally, pixel refs are
-  // clumped into tile grid buckets, so there may be false positives.
-  class CC_EXPORT Iterator {
-   public:
-    // Default iterator constructor that is used as place holder for invalid
-    // Iterator.
-    Iterator();
-    Iterator(const gfx::Rect& layer_rect, const Picture* picture);
-    ~Iterator();
-
-    SkPixelRef* operator->() const {
-      DCHECK_LT(current_index_, current_pixel_refs_->size());
-      return (*current_pixel_refs_)[current_index_];
-    }
-
-    SkPixelRef* operator*() const {
-      DCHECK_LT(current_index_, current_pixel_refs_->size());
-      return (*current_pixel_refs_)[current_index_];
-    }
-
-    Iterator& operator++();
-    operator bool() const {
-      return current_index_ < current_pixel_refs_->size();
-    }
-
-   private:
-    static base::LazyInstance<PixelRefs> empty_pixel_refs_;
-    const PixelRefMap* target_pixel_ref_map_;
-    const PixelRefs* current_pixel_refs_;
-    unsigned current_index_;
-
-    gfx::Rect layer_rect_;
-
-    gfx::Point min_point_;
-    gfx::Point max_point_;
-    int current_x_;
-    int current_y_;
-  };
-
- private:
-  gfx::Point min_pixel_cell_;
-  gfx::Point max_pixel_cell_;
-  gfx::Size cell_size_;
-
-  PixelRefHashmap data_hash_map_;
-};
-
-}  // namespace cc
-
-#endif  // CC_RESOURCES_PIXEL_REF_MAP_H_