Bug 1227190. Make the constructor for ReportExceptionClosure explicit to silence our static analyzers. r=CLOSED TREE

js/src/vm/Debugger.cpp

@@ -979,7 +979,7 @@ namespace {
 class MOZ_STACK_CLASS ReportExceptionClosure : public ScriptEnvironmentPreparer::Closure
 {
 public:
-    ReportExceptionClosure(RootedValue& exn)
+    explicit ReportExceptionClosure(RootedValue& exn)
         : exn_(exn)
     {
     }