Merge "hwui: fix possible null pointer de-refrence"

libs/hwui/LayerRenderer.cpp

@@ -339,8 +339,10 @@ void LayerRenderer::destroyLayerDeferred(Layer* layer) {
 
 void LayerRenderer::flushLayer(Layer* layer) {
 #ifdef GL_EXT_discard_framebuffer
+    if (!layer) return;
+
     GLuint fbo = layer->getFbo();
-    if (layer && fbo) {
+    if (fbo) {
         // If possible, discard any enqueud operations on deferred
         // rendering architectures
         if (Extensions::getInstance().hasDiscardFramebuffer()) {