Trace RenderLayer::paint

R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/851473005
diff --git a/sky/engine/core/rendering/RenderLayer.cpp b/sky/engine/core/rendering/RenderLayer.cpp
index 12a0ab7..b677b07 100644
--- a/sky/engine/core/rendering/RenderLayer.cpp
+++ b/sky/engine/core/rendering/RenderLayer.cpp
@@ -828,6 +828,7 @@
 
 void RenderLayer::paint(GraphicsContext* context, const LayoutRect& damageRect, RenderObject* paintingRoot)
 {
+    TRACE_EVENT0("blink", "RenderLayer::paint");
     LayerPaintingInfo paintingInfo(this, enclosingIntRect(damageRect), LayoutSize(), paintingRoot);
     paintLayer(context, paintingInfo, PaintContent);
 }