Speculative revert by sheriff

cc/resources/drawing_display_item.cc

Index: cc/resources/drawing_display_item.cc
diff --git a/cc/resources/drawing_display_item.cc b/cc/resources/drawing_display_item.cc
index 91ab3fb0d38103b37a08a0ab9e8a9c25df79ee49..648f9de60a2938eb3b7d77a21a9c2c34d8ae6232 100644
--- a/cc/resources/drawing_display_item.cc
+++ b/cc/resources/drawing_display_item.cc
@@ -34,6 +34,17 @@ void DrawingDisplayItem::Raster(SkCanvas* canvas,
   canvas->restore();
 }
 
+void DrawingDisplayItem::RasterForTracing(SkCanvas* canvas) const {
+  canvas->save();
+  // The picture debugger in about:tracing doesn't drill down into |drawPicture|
+  // operations. Calling |playback()| rather than |drawPicture()| causes the
+  // skia operations in |picture_| to appear individually in the picture
+  // produced for tracing rather than being hidden inside a drawPicture
+  // operation.
+  picture_->playback(canvas);
+  canvas->restore();
+}
+
 bool DrawingDisplayItem::IsSuitableForGpuRasterization() const {
   return picture_->suitableForGpuRasterization(NULL);
 }