Revert 198272 "cc: Move canvas clear from picture to picture_pil..."

cc/resources/picture.cc

Index: cc/resources/picture.cc
===================================================================
--- cc/resources/picture.cc	(revision 205297)
+++ cc/resources/picture.cc	(working copy)
@@ -198,6 +198,16 @@
   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)