Move second internal recursion to a precomputation in layer_tree_host_common.cc

cc/layer_impl.h

 // Copyright 2011 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_LAYER_IMPL_H_
 #define CC_LAYER_IMPL_H_
 
 #include <public/WebFilterOperations.h>
 #include <string>
 
@@ skipping 81 matching lines @@
     virtual RenderPass::Id firstContributingRenderPassId() const;
     virtual RenderPass::Id nextContributingRenderPassId(RenderPass::Id) const;
 
     // Returns true if this layer has content to draw.
     void setDrawsContent(bool);
     bool drawsContent() const { return m_drawsContent; }
 
     bool forceRenderSurface() const { return m_forceRenderSurface; }
     void setForceRenderSurface(bool force) { m_forceRenderSurface = force; }
 
-    // Returns 0 if none of the layer's descendants has content to draw,
-    // 1 if exactly one descendant has content to draw, or a number >1
-    // (but necessary the exact number of descendants) otherwise.
-    virtual int descendantsDrawContent();
+    // This value does not consider the layer itself, only its descendants.
+    virtual int numDescendantsThatDrawContent() { return m_numDescendantsThatDrawContent; }

[danakj, 2012/12/03 18:33:41]

i like the function name

+    void setNumDescendantsThatDrawContent(int num) { m_numDescendantsThatDrawContent = num; }

[danakj, 2012/12/03 18:33:41]

I kinda don't like this. Set/get seems simple but then sometimes the set does
nothing, even tho the variable would be set on the class. Then maybe members of
layer_impl.cc end up using m_numDescendantsThatDrawContent instead of the
function and have the wrong value..

It seems awkward to me.

 
     void setAnchorPoint(const gfx::PointF&);
     const gfx::PointF& anchorPoint() const { return m_anchorPoint; }
 
     void setAnchorPointZ(float);
     float anchorPointZ() const { return m_anchorPointZ; }
 
     void setBackgroundColor(SkColor);
     SkColor backgroundColor() const { return m_backgroundColor; }
 
@@ skipping 300 matching lines @@
     gfx::Rect m_clipRect;
 
     // True if the layer is clipped by m_clipRect.
     bool m_isClipped;
 
     // Rect indicating what was repainted/updated during update.
     // Note that plugin layers bypass this and leave it empty.
     // Uses layer's content space.
     gfx::RectF m_updateRect;
 
+    bool m_numDescendantsThatDrawContent;

[slavi, 2012/12/03 21:33:42]

That should be an int.

+
     // Manages animations for this layer.
     scoped_ptr<LayerAnimationController> m_layerAnimationController;
 
     // Manages scrollbars for this layer
     scoped_ptr<ScrollbarAnimationController> m_scrollbarAnimationController;
 
     DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 void sortLayers(std::vector<LayerImpl*>::iterator first, std::vector<LayerImpl*>::iterator end, LayerSorter*);
 
 }
 
 #endif  // CC_LAYER_IMPL_H_