Reduce namespace pollution.

This leaves us with just the mspace stuff and three libdex functions to clean
up. We deliberately expose the JII API, and I don't think there's anything we
can really do about the art_..._from_code stuff (and at least that starts with
"art_").

Change-Id: I77e58e8330cd2afeb496642302dfe3311e68091a
diff --git a/src/compiler/codegen/arm/LocalOptimizations.cc b/src/compiler/codegen/arm/LocalOptimizations.cc
index b2bc333..eba701b 100644
--- a/src/compiler/codegen/arm/LocalOptimizations.cc
+++ b/src/compiler/codegen/arm/LocalOptimizations.cc
@@ -19,6 +19,8 @@
 #include "ArmLIR.h"
 #include "Codegen.h"
 
+namespace art {
+
 #define DEBUG_OPT(X)
 
 /* Check RAW, WAR, and WAR dependency on the register operands */
@@ -446,3 +448,5 @@
         applyLoadHoisting(cUnit, (ArmLIR* ) headLIR, (ArmLIR* ) tailLIR);
     }
 }
+
+}  // namespace art