Introduce Property Trees

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index f37218642e13259fbfaa0822c412b380d20bfa85..3cd41034bc017af833cdfbd8b658a3792e4ddc9c 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -24,6 +24,7 @@
 #include "cc/layers/paint_properties.h"
 #include "cc/layers/render_surface.h"
 #include "cc/output/filter_operations.h"
+#include "cc/trees/property_tree.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
@@ -180,7 +181,7 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   bool transform_is_invertible() const { return transform_is_invertible_; }
 
   void SetTransformOrigin(const gfx::Point3F&);
-  gfx::Point3F transform_origin() { return transform_origin_; }
+  gfx::Point3F transform_origin() const { return transform_origin_; }
 
   void SetScrollParent(Layer* parent);
 
@@ -245,6 +246,10 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   gfx::Rect visible_content_rect() const {
     return draw_properties_.visible_content_rect;
   }
+  bool has_render_target() const {

[enne (OOO), 2014/12/10 23:45:59]

What does this mean? When does something not have a render target?

[Ian Vollick, 2014/12/12 03:01:47]

Yeah, this surprised me too. It can happen when, eg, an ancestor has a singular
transform and the subtree is skipped. Checking !!render_target() is a no-go in
this case because the DCHECK gets tripped.

[enne (OOO), 2014/12/12 19:05:48]

If the subtree is skipped, why are you asking for its draw transform? etc?

[Ian Vollick, 2014/12/15 21:45:17]

Turns out that there are quite a few reasons we skip layers. Relying on the
presence of the render target turned out to be just a shortcut, preventing me
from writing this logic. I've updated draw_property_utils with this logic (see
FindLayersThatNeedVisibleRects).

+    return draw_properties_.render_target &&
+           draw_properties_.render_target->render_surface();
+  }
   Layer* render_target() {
     DCHECK(!draw_properties_.render_target ||
            draw_properties_.render_target->render_surface());
@@ -457,11 +462,39 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
     needs_push_properties_ = false;
   }
 
+  bool NeedsVisibleRectUpdated() const;
+
   virtual void RunMicroBenchmark(MicroBenchmark* benchmark);
 
   void Set3dSortingContextId(int id);
   int sorting_context_id() const { return sorting_context_id_; }
 
+  void set_transform_tree_index(int index) { transform_tree_index_ = index; }
+  void set_clip_tree_index(int index) { clip_tree_index_ = index; }
+  int clip_tree_index() const { return clip_tree_index_; }
+  int transform_tree_index() const { return transform_tree_index_; }
+
+  void set_offset_to_transform_parent(gfx::Vector2dF offset) {
+    offset_to_transform_parent_ = offset;
+  }
+  gfx::Vector2dF offset_to_transform_parent() const {
+    return offset_to_transform_parent_;
+  }
+
+  // TODO(vollick): Once we transition to transform and clip trees, rename these
+  // functions and related values.  The "debug" functions below use the
+  // transform and clip trees.  Eventually, we will use these functions to
+  // compute the official values, but these functions are retained for testing
+  // purposes until we've migrated.
+
+  const gfx::Rect& debug_visible_rect() const { return debug_visible_rect_; }

[enne (OOO), 2014/12/10 23:45:59]

bikeshedding, but maybe visible_rect_from_property_tree? Debug isn't really an
amazing name.

[Ian Vollick, 2014/12/12 03:01:47]

Done.

+  void set_debug_visible_rect(const gfx::Rect& rect) {
+    debug_visible_rect_ = rect;
+  }
+
+  gfx::Transform debug_screen_space_transform(const TransformTree& tree) const;
+  gfx::Transform debug_draw_transform(const TransformTree& tree) const;
+
  protected:
   friend class LayerImpl;
   friend class TreeSynchronizer;
@@ -589,6 +622,10 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   // this layer.
   int scroll_clip_layer_id_;
   int num_descendants_that_draw_content_;
+  int transform_tree_index_;
+  int opacity_tree_index_;
+  int clip_tree_index_;
+  gfx::Vector2dF offset_to_transform_parent_;
   bool should_scroll_on_main_thread_ : 1;
   bool have_wheel_event_handlers_ : 1;
   bool have_scroll_event_handlers_ : 1;
@@ -641,6 +678,7 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
 
   PaintProperties paint_properties_;
 
+  gfx::Rect debug_visible_rect_;
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };