Move TaskRunner to details

Bug: 36433220
Test: compiles
Test: hidl_test
Change-Id: Id10c9b7bc2822f05e8720e55edd7aa113c58ad15
diff --git a/generateCpp.cpp b/generateCpp.cpp
index 5164c73..881d31e 100644
--- a/generateCpp.cpp
+++ b/generateCpp.cpp
@@ -1814,7 +1814,7 @@
     out << "const ::android::sp<" << ifaceName << "> mImpl;\n";
 
     if (supportOneway) {
-        out << "::android::hardware::TaskRunner mOnewayQueue;\n";
+        out << "::android::hardware::details::TaskRunner mOnewayQueue;\n";
 
         out << "\n";