[cc] Move root layer pointer to LayerTreeImpl

cc/layer_tree_host.cc

Index: cc/layer_tree_host.cc
diff --git a/cc/layer_tree_host.cc b/cc/layer_tree_host.cc
index 587a4144c30b365f92388304ea0f565005b50393..14bb08bd5450493db86c1fa9d4c28a30b9268e57 100644
--- a/cc/layer_tree_host.cc
+++ b/cc/layer_tree_host.cc
@@ -372,16 +372,16 @@ void LayerTreeHost::finishCommitOnImplThread(LayerTreeHostImpl* hostImpl)
     m_needsFullTreeSync = false;
 
     if (m_rootLayer && m_hudLayer)
-        hostImpl->setHudLayer(static_cast<HeadsUpDisplayLayerImpl*>(LayerTreeHostCommon::findLayerInSubtree(hostImpl->rootLayer(), m_hudLayer->id())));
+        hostImpl->activeTree()->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(LayerTreeHostCommon::findLayerInSubtree(hostImpl->rootLayer(), m_hudLayer->id())));
     else
-        hostImpl->setHudLayer(0);
+        hostImpl->activeTree()->set_hud_layer(0);
 
     // We may have added an animation during the tree sync. This will cause both layer tree hosts
     // to visit their controllers.
     if (rootLayer() && m_needsAnimateLayers)
         hostImpl->setNeedsAnimateLayers();
 
-    hostImpl->setSourceFrameNumber(commitNumber());
+    hostImpl->activeTree()->set_source_frame_number(commitNumber());
     hostImpl->setViewportSize(layoutViewportSize(), deviceViewportSize());
     hostImpl->setDeviceScaleFactor(deviceScaleFactor());

[enne (OOO), 2012/12/05 23:09:09]

I kind of wonder if most of these other things are tree-specific state, since
they're tied to this commit.

Also, I'm assuming that all uses of activeTree() in this function will become
pendingTree() when that exists?

     hostImpl->setPageScaleFactorAndLimits(m_pageScaleFactor, m_minPageScaleFactor, m_maxPageScaleFactor);