Replace "using namespace" statement with individual "using" statements

components/nacl/loader/nonsfi/nonsfi_sandbox.cc

Index: components/nacl/loader/nonsfi/nonsfi_sandbox.cc
diff --git a/components/nacl/loader/nonsfi/nonsfi_sandbox.cc b/components/nacl/loader/nonsfi/nonsfi_sandbox.cc
index ac3fa9905b261145d3ddc4c2abadc3aec670989f..35ee417d2051e2ddfb720f879e7d0e5c86ce8382 100644
--- a/components/nacl/loader/nonsfi/nonsfi_sandbox.cc
+++ b/components/nacl/loader/nonsfi/nonsfi_sandbox.cc
@@ -28,10 +28,19 @@
 #define MAP_STACK 0x20000
 #endif
 
-using namespace sandbox::bpf_dsl;
 using sandbox::CrashSIGSYS;
 using sandbox::CrashSIGSYSClone;
 using sandbox::CrashSIGSYSPrctl;
+using sandbox::bpf_dsl::Allow;
+using sandbox::bpf_dsl::Arg;
+using sandbox::bpf_dsl::Error;
+using sandbox::bpf_dsl::If;
+using sandbox::bpf_dsl::ResultExpr;
+
+// TODO(mdempsky): Make BoolExpr a standalone class so these operators can
+// be resolved via argument-dependent lookup.
+using sandbox::bpf_dsl::operator&&;
+using sandbox::bpf_dsl::operator||;
 
 namespace nacl {
 namespace nonsfi {