Finish shadow support in new reorderer/renderer

Now passes alphas and light radius, and correctly transforms light
center for layers.

Also fixes begin-frame/layer clears to be damage rect aware.

Change-Id: I3b1415cd7bf1518c510145ebebdb745f494a2542
diff --git a/libs/hwui/RenderNode.cpp b/libs/hwui/RenderNode.cpp
index e177f9a..2713f46 100644
--- a/libs/hwui/RenderNode.cpp
+++ b/libs/hwui/RenderNode.cpp
@@ -326,15 +326,11 @@
         return;
     }
 
-    if (transformUpdateNeeded) {
+    if (transformUpdateNeeded && mLayer) {
         // update the transform in window of the layer to reset its origin wrt light source position
         Matrix4 windowTransform;
         info.damageAccumulator->computeCurrentTransform(&windowTransform);
-#if HWUI_NEW_OPS
-        // TODO: update layer transform (perhaps as part of enqueueLayerWithDamage)
-#else
         mLayer->setWindowTransform(windowTransform);
-#endif
     }
 
 #if HWUI_NEW_OPS