Fix crash regression when calling setSurface(null)

Test: HardwareRendererTests#testSetNullSurface
Fixes: 165335939
Change-Id: I8f93a0b6a115088af634e21e91b95b4f6a521f12
diff --git a/libs/hwui/renderthread/RenderProxy.cpp b/libs/hwui/renderthread/RenderProxy.cpp
index aad0cca..b51f6dc 100644
--- a/libs/hwui/renderthread/RenderProxy.cpp
+++ b/libs/hwui/renderthread/RenderProxy.cpp
@@ -77,10 +77,10 @@
 }
 
 void RenderProxy::setSurface(ANativeWindow* window, bool enableTimeout) {
-    ANativeWindow_acquire(window);
+    if (window) { ANativeWindow_acquire(window); }
     mRenderThread.queue().post([this, win = window, enableTimeout]() mutable {
         mContext->setSurface(win, enableTimeout);
-        ANativeWindow_release(win);
+        if (win) { ANativeWindow_release(win); }
     });
 }