Aura: Resize locks with --ui-enable-threaded-compositing

cc/tree_synchronizer.cc

Index: cc/tree_synchronizer.cc
diff --git a/cc/tree_synchronizer.cc b/cc/tree_synchronizer.cc
index b7e76bbe9ab16d6843bfb26937329c17e35b6233..d7f63cb98b8adf9d83a2ec6eb44afb10cc51f530 100644
--- a/cc/tree_synchronizer.cc
+++ b/cc/tree_synchronizer.cc
@@ -19,7 +19,7 @@ scoped_ptr<CCLayerImpl> TreeSynchronizer::synchronizeTrees(LayerChromium* layerC
     ScopedPtrCCLayerImplMap oldLayers;
     RawPtrCCLayerImplMap newLayers;
 
-    collectExistingCCLayerImplRecursive(oldLayers, oldCCLayerImplRoot.Pass());
+    collectExistingCCLayerImplRecursive(layerChromiumRoot, oldLayers, oldCCLayerImplRoot.Pass());
 
     scoped_ptr<CCLayerImpl> newTree = synchronizeTreeRecursive(newLayers, oldLayers, layerChromiumRoot, hostImpl);
 
@@ -28,17 +28,26 @@ scoped_ptr<CCLayerImpl> TreeSynchronizer::synchronizeTrees(LayerChromium* layerC
     return newTree.Pass();
 }
 
-void TreeSynchronizer::collectExistingCCLayerImplRecursive(ScopedPtrCCLayerImplMap& oldLayers, scoped_ptr<CCLayerImpl> ccLayerImpl)
+void TreeSynchronizer::collectExistingCCLayerImplRecursive(LayerChromium* layer, ScopedPtrCCLayerImplMap& oldLayers, scoped_ptr<CCLayerImpl> ccLayerImpl)
 {
-    if (!ccLayerImpl)
+    if (!layer || !ccLayerImpl || layer->id() != ccLayerImpl->id())
         return;
 
-    ScopedPtrVector<CCLayerImpl>& children = ccLayerImpl->m_children;
-    for (size_t i = 0; i < children.size(); ++i)
-        collectExistingCCLayerImplRecursive(oldLayers, children.take(i));
+    if (!layer->deferUpdates()) {
+        ScopedPtrVector<CCLayerImpl>& oldChildren = ccLayerImpl->m_children;
+        ScopedPtrCCLayerImplMap oldChildrenMap;
+        for (size_t i = 0; i < oldChildren.size(); ++i) {
+            int oldChildId = oldChildren[i]->id();
+            oldChildrenMap.set(oldChildId, oldChildren.take(i));
+        }
 
-    collectExistingCCLayerImplRecursive(oldLayers, ccLayerImpl->m_maskLayer.Pass());
-    collectExistingCCLayerImplRecursive(oldLayers, ccLayerImpl->m_replicaLayer.Pass());
+        const LayerChromium::LayerList& children = layer->children();
+        for (size_t i = 0; i < children.size(); ++i)
+            collectExistingCCLayerImplRecursive(children[i].get(), oldLayers, oldChildrenMap.take(children[i]->id()));

[piman, 2012/10/17 21:26:32]

Why is it a problem to collect all the older layers?

[jonathan.backer, 2012/10/18 20:20:35]

Collecting all the old layers detroys the LayerImpl tree structure, which I want
to partially reuse.

My understanding of how the code used to work is:
- collect all the old LayerImpls
- traverse the Layer tree and reuse as many LayerImpls as possible
- discard the LayerImpls we didn't reuse

Now I want to skip those subtrees of the Layer tree rooted at a deferUpdates
(the tree structure may have changed since last commit). In this case, I to
reuse the corresponding tree structure that I had in the LayerImpl tree.

+
+        collectExistingCCLayerImplRecursive(layer->maskLayer(), oldLayers, ccLayerImpl->m_maskLayer.Pass());
+        collectExistingCCLayerImplRecursive(layer->replicaLayer(), oldLayers, ccLayerImpl->m_replicaLayer.Pass());
+    }
 
     int id = ccLayerImpl->id();
     oldLayers.set(id, ccLayerImpl.Pass());
@@ -60,6 +69,9 @@ scoped_ptr<CCLayerImpl> TreeSynchronizer::synchronizeTreeRecursive(RawPtrCCLayer
     if (!layer)
         return scoped_ptr<CCLayerImpl>();
 
+    if (layer->deferUpdates())
+        return oldLayers.take(layer->id());
+
     scoped_ptr<CCLayerImpl> ccLayerImpl = reuseOrCreateCCLayerImpl(newLayers, oldLayers, layer);
 
     ccLayerImpl->clearChildList();