Fix google-build-using-namespace warnings in rs.

* Most files define classes in renderscript namespace.
  Define them in the namespace instead of "using namespace ...".
  Some files define global C++ names, and we replace
  "using namespace ..." with using declarations of the required names.
* Add "NOLINT" comment to rsg_generator.c output code to suppress
  such warnings.

Bug: 32670901
Test: build with WITH_TIDY=1
Change-Id: I9b0edcad3e1fb37c79927b05fd58fb1a301bdf22
diff --git a/rsMesh.cpp b/rsMesh.cpp
index f6fbaf6..bd3070d 100644
--- a/rsMesh.cpp
+++ b/rsMesh.cpp
@@ -18,8 +18,8 @@
 #include "rsMesh.h"
 #include "rs.h"
 
-using namespace android;
-using namespace android::renderscript;
+namespace android {
+namespace renderscript {
 
 Mesh::Mesh(Context *rsc) : ObjectBase(rsc) {
     mHal.drv = nullptr;
@@ -263,9 +263,6 @@
     }
 }
 
-namespace android {
-namespace renderscript {
-
 RsMesh rsi_MeshCreate(Context *rsc,
                       RsAllocation * vtx, size_t vtxCount,
                       RsAllocation * idx, size_t idxCount,
@@ -287,4 +284,5 @@
     return sm;
 }
 
-}}
+} // namespace renderscript
+} // namespace android