cc: Skip analysis for narrow layers.

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index 8dc9c29ff0ae4527fc343c60bf58bf7b88a6092f..0ac17a29094938c08a97475bdb179d065d570b64 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -32,6 +32,9 @@ namespace {
 // a tile is of solid color.
 const bool kUseColorEstimator = true;
 
+// Minimum width/height of a pile that would require analysis for tiles.
+const int kMinLengthToAnalyze = 256;

[reveman, 2014/03/27 18:11:26]

kMinDimensionForAnalysis?

[vmpstr, 2014/03/27 18:41:27]

Done.

+
 class DisableLCDTextFilter : public SkDrawFilter {
  public:
   // SkDrawFilter interface.
@@ -1163,7 +1166,14 @@ scoped_refptr<internal::RasterWorkerPoolTask> TileManager::CreateRasterTask(
   // It is drawn directly as a solid-color quad saving raster and upload cost.
   // The analysis step is however expensive and is not justified when doing
   // gpu rasterization where there is no upload.
-  bool analyze_picture = !tile->use_gpu_rasterization();
+  //
+  // Additionally, we do not want to do the analysis if the layer that produced
+  // this tile is narrow, since more likely than not the tile would not be
+  // solid.
+  gfx::Size pile_size = tile->picture_pile()->size();
+  bool analyze_picture =
+      !tile->use_gpu_rasterization() &&
+      std::min(pile_size.width(), pile_size.height()) >= kMinLengthToAnalyze;

[reveman, 2014/03/27 18:11:26]

Comment mentions layer but you use the picture pile size. Are they always the
same?

[vmpstr, 2014/03/27 18:41:27]

I think it has to be the same. In any case, if it's smaller than the constant,
that means the layer is smaller. I've added a comment to elaborate of that.

 
   return make_scoped_refptr(new RasterWorkerPoolTaskImpl(
       const_resource,