[Blimp client] Move client code into blimp::client namespace

blimp/client/session/render_widget_feature_unittest.cc

Index: blimp/client/session/render_widget_feature_unittest.cc
diff --git a/blimp/client/session/render_widget_feature_unittest.cc b/blimp/client/session/render_widget_feature_unittest.cc
index aeb4eb07e786aa55357b95cce682ddfc5154c53c..9629fde777b29a56a64ff851335276accfa5803f 100644
--- a/blimp/client/session/render_widget_feature_unittest.cc
+++ b/blimp/client/session/render_widget_feature_unittest.cc
@@ -21,6 +21,7 @@ using testing::InSequence;
 using testing::Sequence;
 
 namespace blimp {
+namespace client {
 
 namespace {
 
@@ -126,4 +127,5 @@ TEST_F(RenderWidgetFeatureTest, RepliesHaveCorrectRenderWidgetId) {
   feature_.SendCompositorMessage(2, cc::proto::CompositorMessage());
 }
 
+}  // namespace client
 }  // namespace blimp