Move runner stuff into a runner namespace.

mojo/runner/android/main.cc

Index: mojo/runner/android/main.cc
diff --git a/mojo/runner/android/main.cc b/mojo/runner/android/main.cc
index a610f2207f0b2d2bc19b6b3bed97fec0508a1a4b..82ba0b4a571c31d7b212f73ea89fc3e8de387c42 100644
--- a/mojo/runner/android/main.cc
+++ b/mojo/runner/android/main.cc
@@ -33,7 +33,7 @@
 using base::LazyInstance;
 
 namespace mojo {
-namespace shell {
+namespace runner {
 
 namespace {
 
@@ -201,7 +201,7 @@ bool RegisterShellMain(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
-}  // namespace shell
+}  // namespace runner
 }  // namespace mojo
 
 // TODO(vtl): Even though main() should never be called, mojo_shell fails to