Move second internal recursion to a precomputation in layer_tree_host_common.cc

cc/draw_properties.h

 // Copyright 2012 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_DRAW_PROPERTIES_H_
 #define CC_DRAW_PROPERTIES_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
 
 // Container for properties that layers need to compute before they can be
 // drawn.
 template<typename LayerType, typename RenderSurfaceType>
 struct CC_EXPORT DrawProperties {
     DrawProperties()
         : opacity(0)
         , opacity_is_animating(false)
         , target_space_transform_is_animating(false)
         , screen_space_transform_is_animating(false)
         , is_clipped(false)
         , render_target(0)
+        , num_descendants_that_draw_content(0)
     {
     }
 
     // Transforms objects from content space to target surface space, where
     // this layer would be drawn.
     gfx::Transform target_space_transform;
 
     // Transforms objects from content space to screen space (viewport space).
     gfx::Transform screen_space_transform;
 
@@ skipping 25 matching lines @@
     gfx::Rect visible_content_rect;
 
     // In target surface space, the rect that encloses the clipped, drawable
     // content of the layer.
     gfx::Rect drawable_content_rect;
 
     // In target surface space, the original rect that clipped this
     // layer. This value is used to avoid unnecessarily changing GL scissor
     // state.
     gfx::Rect clip_rect;
+
+    // Does not include this layer itself, only its children and descendants.
+    int num_descendants_that_draw_content;
 };
 
 }  // namespace cc
 
 #endif  // CC_DRAW_PROPERTIES_H_