Introduce Property Trees

cc/trees/draw_property_utils.h

Index: cc/trees/draw_property_utils.h
diff --git a/cc/trees/draw_property_utils.h b/cc/trees/draw_property_utils.h
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+++ b/cc/trees/draw_property_utils.h
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+// 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_TREES_DRAW_PROPERTY_UTILS_H_
+#define CC_TREES_DRAW_PROPERTY_UTILS_H_
+
+#include "cc/base/cc_export.h"
+
+namespace gfx {
+class Rect;
+class Transform;
+}  // namespace gfx
+
+namespace cc {
+
+class ClipTree;
+class Layer;
+class TransformTree;
+
+// Computes combined clips for every node in |clip_tree|. This function requires
+// that |transform_tree| has been updated via |ComputeTransforms|.
+// TODO(vollick): ComputeClips and ComputeTransforms will eventually need to be
+// done on both threads.
+void CC_EXPORT
+ComputeClips(ClipTree* clip_tree, const TransformTree& transform_tree);
+
+// Computes combined (screen space) transforms for every node in the transform
+// tree. This must be done prior to calling |ComputeClips|.
+void CC_EXPORT ComputeTransforms(TransformTree* transform_tree);
+
+// Computes the visible content rect for every layer under |root_layer|. The
+// visible content rect is the clipped content space rect that will be used for
+// recording.
+void CC_EXPORT
+ComputeVisibleRectsUsingPropertyTrees(Layer* root_layer,
+                                      const Layer* page_scale_layer,
+                                      float page_scale_factor,
+                                      float device_scale_factor,
+                                      const gfx::Rect& viewport,
+                                      const gfx::Transform& device_transform,
+                                      TransformTree* transform_tree,
+                                      ClipTree* clip_tree);
+
+}  // namespace cc
+
+#endif  // CC_TREES_DRAW_PROPERTY_UTILS_H_