Activate LayerImpl tree with sync+push instead of pointer swap

cc/picture_pile_impl.cc

Index: cc/picture_pile_impl.cc
diff --git a/cc/picture_pile_impl.cc b/cc/picture_pile_impl.cc
index 4155664f79ad3396e2938ac5472527446ee930d4..9ec857f8293cee1d889430ecae19544755a871cd 100644
--- a/cc/picture_pile_impl.cc
+++ b/cc/picture_pile_impl.cc
@@ -99,6 +99,12 @@ void PicturePileImpl::GatherPixelRefs(
   }
 }
 
+void PicturePileImpl::PushPropertiesTo(PicturePileImpl* other) {

[enne (OOO), 2013/01/17 23:34:55]

You should just call PicturePileBase::PushPropertiesTo and then just copy the
clones here.

[jamesr, 2013/01/18 01:16:42]

Ah, missed that there was a base class.  Done

+  other->pile_ = pile_;
+  other->clones_ = clones_;
+  other->min_contents_scale_ = min_contents_scale_;
+}
+
 skia::RefPtr<SkPicture> PicturePileImpl::GetFlattenedPicture() {
   TRACE_EVENT0("cc", "PicturePileImpl::GetFlattenedPicture");