Nest all namespaces

The compiler supports this now.  We can type less going forward.
No functional changes.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I29d6fa4f9aacc0e381f1a7637294db0392466995
diff --git a/aos/actions/action_test.cc b/aos/actions/action_test.cc
index ea46ed8..c7c3c48 100644
--- a/aos/actions/action_test.cc
+++ b/aos/actions/action_test.cc
@@ -13,10 +13,7 @@
 #include "aos/events/simulated_event_loop.h"
 #include "aos/testing/path.h"
 
-namespace aos {
-namespace common {
-namespace actions {
-namespace testing {
+namespace aos::common::actions::testing {
 
 namespace chrono = ::std::chrono;
 
@@ -515,7 +512,4 @@
   event_loop_factory_.RunFor(chrono::seconds(2));
 }
 
-}  // namespace testing
-}  // namespace actions
-}  // namespace common
-}  // namespace aos
+}  // namespace aos::common::actions::testing
diff --git a/aos/actions/actions.cc b/aos/actions/actions.cc
index 764cb6c..133101b 100644
--- a/aos/actions/actions.cc
+++ b/aos/actions/actions.cc
@@ -1,8 +1,6 @@
 #include "aos/actions/actions.h"
 
-namespace aos {
-namespace common {
-namespace actions {
+namespace aos::common::actions {
 
 void ActionQueue::EnqueueAction(::std::unique_ptr<Action> action) {
   if (current_action_) {
@@ -70,6 +68,4 @@
   return false;
 }
 
-}  // namespace actions
-}  // namespace common
-}  // namespace aos
+}  // namespace aos::common::actions
diff --git a/aos/actions/actor.cc b/aos/actions/actor.cc
index 6a91c74..727b7a9 100644
--- a/aos/actions/actor.cc
+++ b/aos/actions/actor.cc
@@ -1,7 +1 @@
 #include "aos/actions/actor.h"
-
-namespace aos {
-namespace common {
-namespace actions {}  // namespace actions
-}  // namespace common
-}  // namespace aos