Nest some more namespaces

Did someone previously suggest that all namespace had been
nested?  Silly.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I22278c1caaeba8b47dc46fb2ed3078c20a11e190
diff --git a/aos/vision/blob/stream_view.h b/aos/vision/blob/stream_view.h
index 0db69e5..9841ca2 100644
--- a/aos/vision/blob/stream_view.h
+++ b/aos/vision/blob/stream_view.h
@@ -7,8 +7,7 @@
 #include "aos/vision/debug/debug_window.h"
 #include "aos/vision/image/image_types.h"
 
-namespace aos {
-namespace vision {
+namespace aos::vision {
 
 class BlobStreamViewer : public DebugWindow {
  public:
@@ -85,7 +84,6 @@
   ImageValue image_;
 };
 
-}  // namespace vision
-}  // namespace aos
+}  // namespace aos::vision
 
 #endif  // _AOS_VISION_BLOB_STREAM_VIEW_H_