cc: Add some more infrastructure for two trees

cc/picture_layer.cc

Index: cc/picture_layer.cc
diff --git a/cc/picture_layer.cc b/cc/picture_layer.cc
index ca2bf4a2988e8c71b9127b46488506f3fdfa71ee..a7466cb633e47191db5b3526ffd7ead89d53a935 100644
--- a/cc/picture_layer.cc
+++ b/cc/picture_layer.cc
@@ -3,6 +3,8 @@
 // found in the LICENSE file.
 
 #include "cc/picture_layer.h"
+
+#include "cc/layer_tree_impl.h"
 #include "cc/picture_layer_impl.h"
 #include "ui/gfx/rect_conversions.h"
 
@@ -29,15 +31,30 @@ scoped_ptr<LayerImpl> PictureLayer::createLayerImpl(LayerTreeImpl* treeImpl) {
 
 void PictureLayer::pushPropertiesTo(LayerImpl* base_layer) {
   Layer::pushPropertiesTo(base_layer);
+
   PictureLayerImpl* layer_impl = static_cast<PictureLayerImpl*>(base_layer);
-  layer_impl->didUpdateBounds();
+  layer_impl->tilings_.SetLayerBounds(bounds());
+  layer_impl->invalidation_.Clear();
+  layer_impl->invalidation_.Swap(pile_invalidation_);
   pile_.PushPropertiesTo(layer_impl->pile_);
 
-  // TODO(enne): Once we have two trees on the impl side, we need to
-  // sync the active layer's tiles prior to this Invalidate call since it
-  // will make new tiles for anything intersecting the invalidation.
-  layer_impl->tilings_.Invalidate(pile_invalidation_);
-  pile_invalidation_.Clear();
+  // TODO(enne): Remove this once syncing happens to the pending tree rather
+  // than the active one.
+  if (layer_impl->layerTreeImpl()->IsActiveTree()) {
+    layer_impl->tilings_.Invalidate(layer_impl->invalidation_);
+    return;
+  }
+
+  if (drawsContent()) {

[nduca, 2012/12/14 02:18:43]

can this be a method on the picture layer impl? DidSyncFromPendingTree? This
would allow us to build unit tests for this subsystem without having to
instantiate the main thread side layer.

[enne (OOO), 2012/12/14 17:30:53]

Do you mean without having to instantiate an active tree with this layer?

Are you saying that this should set some needs-to-sync flag on the
PictureLayerImpl and the first update that it does does a sync from the other
layer?

+    // If there is an active tree version of this layer, get a copy of its
+    // tiles.  This needs to be done last, after setting invalidation and the
+    // pile.
+    DCHECK(layer_impl->layerTreeImpl()->IsPendingTree());
+    PictureLayerImpl* active_twin = static_cast<PictureLayerImpl*>(
+        base_layer->layerTreeImpl()->ActiveTreeLayerById(id()));
+    if (active_twin)
+      layer_impl->SyncFromActiveLayer(active_twin);
+  }
 }
 
 void PictureLayer::setNeedsDisplayRect(const gfx::RectF& layer_rect) {