Track occlusion per tree on Tile.

cc/resources/tile.h

Index: cc/resources/tile.h
diff --git a/cc/resources/tile.h b/cc/resources/tile.h
index 29acf80a1e35d116e309dde63d4a9f3c8d5aa1a3..108756991d6962dd36d83afc1a7d997dba4666c7 100644
--- a/cc/resources/tile.h
+++ b/cc/resources/tile.h
@@ -128,8 +128,31 @@ class CC_EXPORT Tile : public RefCountedManaged<Tile> {
     return managed_state_.tile_versions[mode];
   }
 
-  void set_is_occluded(bool is_occluded) { is_occluded_ = is_occluded; }
-  bool is_occluded() const { return is_occluded_; }
+  void set_is_occluded(WhichTree tree, bool is_occluded) {
+    switch (tree) {
+      case ACTIVE_TREE:
+        is_occluded_on_active_tree_ = is_occluded;
+        break;
+      case PENDING_TREE:
+        is_occluded_on_pending_tree_ = is_occluded;
+        break;
+      default:

[danakj, 2014/07/07 19:26:29]

don't use default: for enums, then we don't get compiler warnings when we add
another value to the enum. Instead, make each case above return, and just
NOTREACHED() below the switch.

+        NOTREACHED();
+        return;
+    }
+  }
+
+  bool is_occluded(WhichTree tree) const {
+    switch (tree) {
+      case ACTIVE_TREE:
+        return is_occluded_on_active_tree_;

[enne (OOO), 2014/07/07 19:49:31]

Should is_occluded just go on TilePriority so you could say
priority_[ACTIVE_TREE].is_occluded?

[danakj, 2014/07/07 20:08:04]

FWIW, she did that originally but with vlad's new work this seems a little up in
the air. So in the interest of working parallelly, this adds a second bool while
deferring the decision about priority or not.

+      case PENDING_TREE:
+        return is_occluded_on_pending_tree_;
+      default:
+        NOTREACHED();

[danakj, 2014/07/07 19:26:29]

remove default: move this below the switch

or alternatively you could do is_occluded_[NUM_TREES] and have set/get just do
an array index with the tree variable. (like priority_)

[jbedley, 2014/07/07 20:25:13]

Done.

+        return false;
+    }
+  }
 
  private:
   friend class TileManager;
@@ -160,7 +183,8 @@ class CC_EXPORT Tile : public RefCountedManaged<Tile> {
   gfx::Rect content_rect_;
   float contents_scale_;
   gfx::Rect opaque_rect_;
-  bool is_occluded_;
+  bool is_occluded_on_active_tree_;
+  bool is_occluded_on_pending_tree_;
 
   TilePriority priority_[NUM_TREES];
   ManagedTileState managed_state_;