Discard framebuffer rendering queues when discarding layers
Bug #5581817

Change-Id: If612846ec5f7793710fc4df152791fb32c506551
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 32595e4..1a8c1997 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -611,6 +611,11 @@
     }
 
     if (fboLayer) {
+        // Note: No need to use glDiscardFramebufferEXT() since we never
+        //       create/compose layers that are not on screen with this
+        //       code path
+        // See LayerRenderer::destroyLayer(Layer*)
+
         // Detach the texture from the FBO
         glBindFramebuffer(GL_FRAMEBUFFER, current->fbo);
         glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);