Reorganize Layer Hoisting code

src/gpu/GrLayerHoister.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrLayerHoister_DEFINED
+#define GrLayerHoister_DEFINED
+
+#include "SkPicture.h"
+#include "SkTDArray.h"
+
+class GrAccelData;
+struct GrCachedLayer;
+struct SkRect;
+
+// This class collects the layer hoisting functionality in one place.

[bsalomon, 2014/09/02 15:26:20]

namespace?

maybe a little bit more description here about how this is used?

I assume you call FindLayersToHoist() once for each picture, one call to
DrawLayers(), and then UnlockLayers() per-picture.

[robertphillips, 2014/09/02 16:14:42]

It's a class to provide a hook for friending.
Done.

[bsalomon, 2014/09/02 16:58:14]

oh, makes sense.

+class GrLayerHoister {
+public:
+    static bool FindLayersToHoist(const GrAccelData *gpuData,
+                                  const SkPicture::OperationList* ops,
+                                  const SkRect& query,

[bsalomon, 2014/09/02 15:26:20]

pullForward[]?

comments on what the params mean?

[robertphillips, 2014/09/02 16:14:42]

Done.

+                                  bool* pullForward);
+
+    static void DrawLayers(const SkPicture* picture,
+                           const SkTDArray<GrCachedLayer*>& atlased,
+                           const SkTDArray<GrCachedLayer*>& nonAtlased);
+
+    static void UnlockLayers(GrLayerCache* layerCache, const SkPicture* picture);
+};
+
+#endif