cc: Optimize decode scheduling for checker-images.

cc/tiles/tile.h

Index: cc/tiles/tile.h
diff --git a/cc/tiles/tile.h b/cc/tiles/tile.h
index 16d37d1491d88a5f9b7938eada47ed21ea32d2d2..12bc9ec230d6b58625a86f6ba53a4cfde5f39557 100644
--- a/cc/tiles/tile.h
+++ b/cc/tiles/tile.h
@@ -113,6 +113,9 @@ class CC_EXPORT Tile {
     return is_solid_color_analysis_performed_;
   }
 
+  void set_is_checker_imaged() { is_checker_imaged_ = true; }
+  bool is_checker_imaged() const { return is_checker_imaged_; }
+
   const PictureLayerTiling* tiling() const { return tiling_; }
   void set_tiling(const PictureLayerTiling* tiling) { tiling_ = tiling; }
 
@@ -144,6 +147,7 @@ class CC_EXPORT Tile {
   bool required_for_activation_ : 1;
   bool required_for_draw_ : 1;
   bool is_solid_color_analysis_performed_ : 1;
+  bool is_checker_imaged_ = false;
 
   Id id_;