Revert "cc: Move canvas clear from picture to picture_pile_impl"

cc/resources/picture.cc

Index: cc/resources/picture.cc
diff --git a/cc/resources/picture.cc b/cc/resources/picture.cc
index 159885d994b6aa42e01bafce6ea5d630316cd81f..20b517532e807feae401e7e9f6b2e32fda9d22ee 100644
--- a/cc/resources/picture.cc
+++ b/cc/resources/picture.cc
@@ -198,6 +198,16 @@ void Picture::Record(ContentLayerClient* painter,
   canvas->translate(SkFloatToScalar(-layer_rect_.x()),
                     SkFloatToScalar(-layer_rect_.y()));
 
+  SkPaint paint;
+  paint.setAntiAlias(false);
+  paint.setXfermodeMode(SkXfermode::kClear_Mode);
+  SkRect layer_skrect = SkRect::MakeXYWH(layer_rect_.x(),
+                                         layer_rect_.y(),
+                                         layer_rect_.width(),
+                                         layer_rect_.height());
+  canvas->clipRect(layer_skrect);
+  canvas->drawRect(layer_skrect, paint);
+
   gfx::RectF opaque_layer_rect;
   base::TimeTicks begin_record_time;
   if (stats)