Add missing nothingToDraw() check

Fixes: 34598346

Prior to 2874daa4d38bddd3a5f0edb3774d5e5884dd9554 we
never freed the resources of root nodes. Now that this is being
done we need to ensure that the backdrop has content before
we try to draw that content. All other nodes passed in
deferRenderNodeScene check that nothingToDraw() returns false
before drawing them, but that check was missed on the backdrop
node.

Test: manual. open calculator then long-press on recents
Change-Id: I495749161b38b57278bdb60d5f872eeeb2b218d0

1 files changed, 12 insertions, 10 deletions

diff --git a/libs/hwui/FrameBuilder.cpp b/libs/hwui/FrameBuilder.cpp
index a53a55a06964..1d8b021274fe 100644
--- a/libs/hwui/FrameBuilder.cpp
+++ b/libs/hwui/FrameBuilder.cpp
@@ -180,16 +180,18 @@ void FrameBuilder::deferRenderNodeScene(const std::vector< sp<RenderNode> >& nod
         }
     }
 
-    if (!backdrop.isEmpty()) {
-        // content node translation to catch up with backdrop
-        float dx = contentDrawBounds.left - backdrop.left;
-        float dy = contentDrawBounds.top - backdrop.top;
-
-        Rect contentLocalClip = backdrop;
-        contentLocalClip.translate(dx, dy);
-        deferRenderNode(-dx, -dy, contentLocalClip, *nodes[1]);
-    } else {
-        deferRenderNode(*nodes[1]);
+    if (!nodes[1]->nothingToDraw()) {
+        if (!backdrop.isEmpty()) {
+            // content node translation to catch up with backdrop
+            float dx = contentDrawBounds.left - backdrop.left;
+            float dy = contentDrawBounds.top - backdrop.top;
+
+            Rect contentLocalClip = backdrop;
+            contentLocalClip.translate(dx, dy);
+            deferRenderNode(-dx, -dy, contentLocalClip, *nodes[1]);
+        } else {
+            deferRenderNode(*nodes[1]);
+        }
     }
 
     // remaining overlay nodes, simply defer