cc: Remove tilings from recycle tree when active tree removes them.

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 4a7e0c0b0b66ae5bdf20743b65c0f51c69824c0d..cbd27065ac0bf914167243eade8f5e2d39c1973e 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -1195,6 +1195,10 @@ void PictureLayerImpl::CleanUpTilingsOnActiveLayer(
     to_remove.push_back(tiling);
   }
 
+  if (to_remove.empty())
+    return;
+
+  // Remove tilings on this tree and the twin tree.
   for (size_t i = 0; i < to_remove.size(); ++i) {
     const PictureLayerTiling* twin_tiling = GetTwinTiling(to_remove[i]);
     // Only remove tilings from the twin layer if they have
@@ -1205,9 +1209,19 @@ void PictureLayerImpl::CleanUpTilingsOnActiveLayer(
     CHECK_NE(HIGH_RESOLUTION, to_remove[i]->resolution());
     tilings_->Remove(to_remove[i]);
   }
-  DCHECK_GT(tilings_->num_tilings(), 0u);
 
+  DCHECK_GT(tilings_->num_tilings(), 0u);
   SanityCheckTilingState();
+
+  // Also remove tilings from the recycle tree to ensure that recycle tree
+  // doesn't have any unshared tiles.
+  PictureLayerImpl* recycled_twin = static_cast<PictureLayerImpl*>(
+      layer_tree_impl()->FindRecycleTreeLayerById(id()));
+  if (!recycled_twin)
+    return;
+
+  for (size_t i = 0; i < to_remove.size(); ++i)
+    recycled_twin->RemoveTiling(to_remove[i]->contents_scale());

[danakj, 2014/07/17 21:54:48]

We might remove the high res tiling on the recycle tree and then that's going to
DCHECK in SanityCheck.

 }
 
 float PictureLayerImpl::MinimumContentsScale() const {