Fix Recent thumbnails aren't taken when leaving an activity via notification

When taking screenshots we need to use the full drawing state list
instead of the visible list.

Bug: 5186823
Change-Id: I214ee0203aaf8e2c038e44581f7f1ae36edf08c5

services/surfaceflinger/SurfaceFlinger.cpp

@@ -2207,7 +2207,7 @@ status_t SurfaceFlinger::captureScreenImplLocked(DisplayID dpy,
         return BAD_VALUE;
 
     // make sure none of the layers are protected
-    const Vector< sp<LayerBase> >& layers(mVisibleLayersSortedByZ);
+    const LayerVector& layers(mDrawingState.layersSortedByZ);
     const size_t count = layers.size();
     for (size_t i=0 ; i<count ; ++i) {
         const sp<LayerBase>& layer(layers[i]);