Smart layer invalidation for LCD text.

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index a2c951c5275a8952f1c595ec8d6104deab995393..728c8f7d9fe14adca077a090218cb896e411e5c5 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -854,10 +854,7 @@ void PictureLayerImpl::UpdateLCDTextStatus() {
   pending_layer->is_using_lcd_text_ = is_using_lcd_text_;
   pending_layer->pile_ = PicturePileImpl::CreateFromOther(pending_layer->pile_,
                                                           is_using_lcd_text_);
-
-  // TODO(enne): if we tracked text regions, we could just invalidate those
-  // directly rather than tossing away every tile.
-  pending_layer->tilings_->Invalidate(gfx::Rect(bounds()));
+  pending_layer->tilings_->InvalidateTilesWithText();
 }
 
 void PictureLayerImpl::ResetRasterScale() {