Improve multi-window render clipping logic

Fixes: 28125010

Restructures 'scene defer', to implement window backdrop overdraw
avoidance in new render pipeline, and disable clipping to content draw
bounds.

Also restructures FrameBuilder's constructors, to separate out into
multiple defer methods.

Change-Id: I53facb904c1a4a4acc493d8a489921a79a50494e
diff --git a/libs/hwui/tests/common/TestUtils.h b/libs/hwui/tests/common/TestUtils.h
index 5f4ebc0..dbaefa4 100644
--- a/libs/hwui/tests/common/TestUtils.h
+++ b/libs/hwui/tests/common/TestUtils.h
@@ -171,11 +171,9 @@
         syncHierarchyPropertiesAndDisplayListImpl(node.get());
     }
 
-    static std::vector<sp<RenderNode>> createSyncedNodeList(sp<RenderNode>& node) {
-        TestUtils::syncHierarchyPropertiesAndDisplayList(node);
-        std::vector<sp<RenderNode>> vec;
-        vec.emplace_back(node);
-        return vec;
+    static sp<RenderNode>& getSyncedNode(sp<RenderNode>& node) {
+        syncHierarchyPropertiesAndDisplayList(node);
+        return node;
     }
 
     typedef std::function<void(renderthread::RenderThread& thread)> RtCallback;