cc: Split tiling set raster queues into all and required.

cc/resources/tiling_set_raster_queue_required.h

+// 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 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:
+  class TilingIterator {
+   public:
+    TilingIterator();
+    explicit TilingIterator(PictureLayerTiling* tiling,
+                            TilingData* tiling_data);
+    ~TilingIterator();
+
+    operator bool() const { return !!current_tile_; }

[danakj, 2015/01/08 23:24:41]

should this be an operator comparablethingthatisntabool to avoid conversions to
bool by accident? not sure if it matters here compared to a smart pointer.. but
wdyt?

[vmpstr, 2015/01/09 20:21:41]

Can you elaborate? I'm not sure I understand your suggestion :\ In either case
this is a private class so the use is limited, but if there's a safer way to do
this, I'm up for it. Alternatively, we can just not use iterator style class,
and do like IsDone() or something.

[danakj, 2015/01/09 20:28:22]

I mean like this
https://code.google.com/p/chromium/codesearch#chromium/src/skia/ext/refptr.h&...

[vmpstr, 2015/01/09 20:52:42]

Hmm. Not really a fan from the clean code perspective, but this is less error
prone, I agree. I kinda put my own flavour in, let me know if that's OK.

[vmpstr, 2015/01/10 01:44:55]

After some discussion, I've decided to just go with a bool done() const; :)

+    const Tile* operator*() const { return current_tile_; }
+    Tile* operator*() { return current_tile_; }
+    TilingIterator& operator++();
+
+   private:
+    bool TileNeedsRaster(Tile* tile) const {
+      return tile->NeedsRaster() && !tiling_->IsTileOccluded(tile);
+    }
+
+    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_