Issue 5013 - Make parameter const ref when applicable.

src/JsError.h

Index: src/JsError.h
===================================================================
--- a/src/JsError.h
+++ b/src/JsError.h
@@ -19,18 +19,18 @@
 #define ADBLOCK_PLUS_JS_ERROR_H
 
 #include <sstream>
 #include <stdexcept>
 #include <v8.h>
 
 namespace
 {
-  std::string ExceptionToString(const v8::Handle<v8::Value> exception,
-      const v8::Handle<v8::Message> message)
+  std::string ExceptionToString(const v8::Handle<v8::Value>& exception,
+      const v8::Handle<v8::Message>& message)
   {
     std::stringstream error;
     error << *v8::String::Utf8Value(exception);
     if (!message.IsEmpty())
     {
       error << " at ";
       error << *v8::String::Utf8Value(message->GetScriptResourceName());
       error << ":";
@@ -40,14 +40,14 @@
   }
 }
 
 namespace AdblockPlus
 {
   class JsError : public std::runtime_error
   {
   public:
-    JsError(const v8::Handle<v8::Value> exception,
-            const v8::Handle<v8::Message> message);
+    JsError(const v8::Handle<v8::Value>& exception,
+            const v8::Handle<v8::Message>& message);
   };
 }
 
 #endif