Update from https://crrev.com/311145

cc/resources/tiling_set_raster_queue_required.h

Index: cc/resources/tiling_set_raster_queue_required.h
diff --git a/cc/resources/tiling_set_raster_queue_required.h b/cc/resources/tiling_set_raster_queue_required.h
new file mode 100644
index 0000000000000000000000000000000000000000..5feb05be76620bb325ec9859668a09f24de87f2e
--- /dev/null
+++ b/cc/resources/tiling_set_raster_queue_required.h
@@ -0,0 +1,63 @@
+// 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.
+
+#ifndef CC_RESOURCES_TILING_SET_RASTER_QUEUE_REQUIRED_H_
+#define CC_RESOURCES_TILING_SET_RASTER_QUEUE_REQUIRED_H_
+
+#include "cc/base/cc_export.h"
+#include "cc/resources/picture_layer_tiling_set.h"
+#include "cc/resources/raster_tile_priority_queue.h"
+#include "cc/resources/tile.h"
+#include "cc/resources/tiling_set_raster_queue.h"
+
+namespace cc {
+
+// This queue only returns tiles that are required for either activation or
+// draw, as specified by RasterTilePriorityQueue::Type passed in the
+// constructor.
+class CC_EXPORT TilingSetRasterQueueRequired
+    : public NON_EXPORTED_BASE(TilingSetRasterQueue) {
+ public:
+  TilingSetRasterQueueRequired(PictureLayerTilingSet* tiling_set,
+                               RasterTilePriorityQueue::Type type);
+  ~TilingSetRasterQueueRequired() override;
+
+  Tile* Top() override;
+  const Tile* Top() const override;
+  void Pop() override;
+  bool IsEmpty() const override;
+
+ private:
+  // This iterator will return all tiles that are in the NOW bin on the given
+  // tiling. The queue can then use these tiles and further filter them based on
+  // whether they are required or not.
+  class TilingIterator {
+   public:
+    TilingIterator();
+    explicit TilingIterator(PictureLayerTiling* tiling,
+                            TilingData* tiling_data);
+    ~TilingIterator();
+
+    bool done() const { return current_tile_ == nullptr; }
+    const Tile* operator*() const { return current_tile_; }
+    Tile* operator*() { return current_tile_; }
+    TilingIterator& operator++();
+
+   private:
+    PictureLayerTiling* tiling_;
+    TilingData* tiling_data_;
+
+    Tile* current_tile_;
+    TilingData::Iterator visible_iterator_;
+  };
+
+  bool IsTileRequired(const Tile* tile) const;
+
+  TilingIterator iterator_;
+  RasterTilePriorityQueue::Type type_;
+};
+
+}  // namespace cc
+
+#endif  // CC_RESOURCES_TILING_SET_RASTER_QUEUE_REQUIRED_H_