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

cc/tree_synchronizer.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "TreeSynchronizer.h"
 
 #include "CCLayerImpl.h"
 #include "CCScrollbarAnimationController.h"
 #include "CCScrollbarLayerImpl.h"
 #include "LayerChromium.h"
 #include "ScrollbarLayerChromium.h"
 
 namespace cc {
 
 scoped_ptr<CCLayerImpl> TreeSynchronizer::synchronizeTrees(LayerChromium* layerChromiumRoot, scoped_ptr<CCLayerImpl> oldCCLayerImplRoot, CCLayerTreeHostImpl* hostImpl)
 {
     ScopedPtrCCLayerImplMap oldLayers;
     RawPtrCCLayerImplMap newLayers;
 
-    collectExistingCCLayerImplRecursive(oldLayers, oldCCLayerImplRoot.Pass());
+    collectExistingCCLayerImplRecursive(layerChromiumRoot, oldLayers, oldCCLayerImplRoot.Pass());
 
     scoped_ptr<CCLayerImpl> newTree = synchronizeTreeRecursive(newLayers, oldLayers, layerChromiumRoot, hostImpl);
 
     updateScrollbarLayerPointersRecursive(newLayers, layerChromiumRoot);
 
     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());
 }
 
 scoped_ptr<CCLayerImpl> TreeSynchronizer::reuseOrCreateCCLayerImpl(RawPtrCCLayerImplMap& newLayers, ScopedPtrCCLayerImplMap& oldLayers, LayerChromium* layer)
 {
     scoped_ptr<CCLayerImpl> ccLayerImpl = oldLayers.take(layer->id());
 
     if (!ccLayerImpl)
         ccLayerImpl = layer->createCCLayerImpl();
 
     newLayers[layer->id()] = ccLayerImpl.get();
     return ccLayerImpl.Pass();
 }
 
 scoped_ptr<CCLayerImpl> TreeSynchronizer::synchronizeTreeRecursive(RawPtrCCLayerImplMap& newLayers, ScopedPtrCCLayerImplMap& oldLayers, LayerChromium* layer, CCLayerTreeHostImpl* hostImpl)
 {
     if (!layer)
         return scoped_ptr<CCLayerImpl>();
 
+    if (layer->deferUpdates())
+        return oldLayers.take(layer->id());
+
     scoped_ptr<CCLayerImpl> ccLayerImpl = reuseOrCreateCCLayerImpl(newLayers, oldLayers, layer);
 
     ccLayerImpl->clearChildList();
     const std::vector<scoped_refptr<LayerChromium> >& children = layer->children();
     for (size_t i = 0; i < children.size(); ++i)
         ccLayerImpl->addChild(synchronizeTreeRecursive(newLayers, oldLayers, children[i].get(), hostImpl));
 
     ccLayerImpl->setMaskLayer(synchronizeTreeRecursive(newLayers, oldLayers, layer->maskLayer(), hostImpl));
     ccLayerImpl->setReplicaLayer(synchronizeTreeRecursive(newLayers, oldLayers, layer->replicaLayer(), hostImpl));
 
@@ skipping 30 matching lines @@
     ASSERT(ccScrollbarLayerImpl);
     ASSERT(ccScrollLayerImpl);
 
     if (ccScrollbarLayerImpl->orientation() == WebKit::WebScrollbar::Horizontal)
         ccScrollLayerImpl->setHorizontalScrollbarLayer(ccScrollbarLayerImpl);
     else
         ccScrollLayerImpl->setVerticalScrollbarLayer(ccScrollbarLayerImpl);
 }
 
 } // namespace cc