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 199f94766b6c36336a77eb63016be4625ef3f0d3..b4dfbc45220c11a4ca303d5658645037dea0060b 100644
--- a/cc/resources/picture.cc
+++ b/cc/resources/picture.cc
@@ -167,15 +167,7 @@ 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);
+  canvas->clipRect(RectToSkRect(layer_rect_));

[Tom Hudson, 2013/04/30 09:43:59]

Is this clip actually necessary, since we've created the canvas to be exactly
layer_rect size and offset?

[vmpstr, 2013/04/30 17:06:23]

I had it there initially, since I wasn't sure. But it makes that we don't need
it, I removed it.

 
   gfx::RectF opaque_layer_rect;
   base::TimeTicks begin_record_time;