Implement a method to access the non-composited content root layer picture pile.

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index 55f6452ded8bc55344b72f71dc08478de00335a7..f91f2a9a1890ca2e73bae2c0e7aab2731c63a287 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -1724,4 +1724,31 @@ void LayerTreeHostImpl::animateScrollbarsRecursive(LayerImpl* layer, base::TimeT
         animateScrollbarsRecursive(layer->children()[i], time);
 }
 
+// static
+LayerImpl* LayerTreeHostImpl::getNonCompositedContentRootLayerRecursive(LayerImpl* layer)
+{
+    DCHECK(layer);

[enne (OOO), 2013/01/03 23:55:30]

The root layer could be null.  I think it'd be better to just early out than
DCHECK.

[Leandro Graciá Gil, 2013/01/04 00:41:23]

Done.

+
+    if (layer->drawsContent())
+        return layer;
+
+    for (LayerImpl::LayerList::const_iterator it = layer->children().begin();
+            it != layer->children().end(); ++it) {
+        LayerImpl* nccr = getNonCompositedContentRootLayerRecursive(*it);
+        if (nccr)
+            return nccr;
+    }
+
+    return NULL;
+}
+
+scoped_refptr<PicturePileImpl> LayerTreeHostImpl::capturePicturePile()
+{
+    // Non-composited content root is the first drawable picture layer we find
+    // in a depth-first exploration from the root.
+    LayerTreeImpl* tree = pendingTree() ? pendingTree() : activeTree();
+    const LayerImpl* layer = getNonCompositedContentRootLayerRecursive(tree->RootLayer());
+    return layer ? layer->GetPicturePileClone() : scoped_refptr<PicturePileImpl>();
+}
+
 }  // namespace cc