Disable record/reply on user builds.

Hovering at 775900K -> 812324K free memory (adb shell su 0 procrank)
24150K -> 18801K for 64-bit hidl-generated libs
  (ls -l system/lib64, sum of size column)

Which is a 22% reduction in binary size of these libraries and a
4.7% increase in free memory.

Test: boot on internal marlin.
Test: build user variant of device to ensure flags are setup correctly.

Change-Id: Iacd76cde44ff45a78afcbf83a2d1ca42f89040a3
diff --git a/generateCpp.cpp b/generateCpp.cpp
index debfefd..3e50c03 100644
--- a/generateCpp.cpp
+++ b/generateCpp.cpp
@@ -759,11 +759,13 @@
         out << "});\n\n";
     } else {
         out << ");\n\n";
+
+        // used by generateCppInstrumentationCall
         if (elidedReturn != nullptr) {
-            out << elidedReturn->type().getCppResultType()
-                << " _hidl_out_"
-                << elidedReturn->name()
-                << " = _hidl_return;\n";
+            out << "#ifdef __ANDROID_DEBUGGABLE__\n"
+                << elidedReturn->type().getCppResultType() << " _hidl_out_" << elidedReturn->name()
+                << " = _hidl_return;\n"
+                << "#endif // __ANDROID_DEBUGGABLE__\n";
         }
         status_t status = generateCppInstrumentationCall(
                 out,
@@ -2050,6 +2052,7 @@
         return err;
     }
 
+    out << "#ifdef __ANDROID_DEBUGGABLE__\n";
     out << "if (UNLIKELY(mEnableInstrumentation)) {\n";
     out.indent();
     out << "std::vector<void *> _hidl_args;\n";
@@ -2143,7 +2146,8 @@
     out.unindent();
     out << "}\n";
     out.unindent();
-    out << "}\n\n";
+    out << "}\n";
+    out << "#endif // __ANDROID_DEBUGGABLE__\n\n";
 
     return OK;
 }