Issue 5013 - Use const JsValue and pass reference where applicable

include/AdblockPlus/JsValue.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 80 matching lines @@
 
     //@{
     /**
      * Sets a property value if this is an object (see `IsObject()`).
      * @param name Property name.
      * @param val Property value.
      */
     void SetProperty(const std::string& name, const std::string& val);
     void SetProperty(const std::string& name, int64_t val);
     void SetProperty(const std::string& name, bool val);
-    void SetProperty(const std::string& name, const JsValue& value);
+    void SetProperty(const std::string& name, const JsValuePtr& value);
     inline void SetProperty(const std::string& name, const char* val)
     {
       SetProperty(name, std::string(val));
     }
     inline void SetProperty(const std::string& name, int val)
     {
       SetProperty(name, static_cast<int64_t>(val));
     }
     //@}
 
@@ skipping 19 matching lines @@
      * Invokes the value as a function (see `IsFunction()`) with single
      * parameter.
      * @param arg A single required parameter.
      * @return Value returned by the function.
      */
     JsValue Call(const JsValue& arg) const;
 
     v8::Local<v8::Value> UnwrapValue() const;
 
     /**
-     * Clone a this value to new one
-     * @return Value clone

[sergei, 2017/04/13 10:57:33]

I think the comment should be different. It does not really clone the value, it
creates a new wrapper around internally held JavaScript handle.

[hub, 2017/04/13 12:06:24]

ok.

+     * Creates a new `JsValue` wrapper for the same JavaScript value.
+     * @return Value new `JsValue`
      */
     JsValue Clone() const;

[sergei, 2017/04/13 10:57:33]

Could you please change it to copy constructor but in another commit.

   protected:
     JsEnginePtr jsEngine;
   private:
     JsValue(JsEnginePtr jsEngine, v8::Handle<v8::Value> value);
     void SetProperty(const std::string& name, v8::Handle<v8::Value> val);
     // Parameter args is not const because a pointer to its internal arrays is
     // passed to v8::Function::Call but the latter does not expect a const pointer.
     JsValue Call(std::vector<v8::Handle<v8::Value>>& args, v8::Local<v8::Object> thisObj) const;
 
     std::unique_ptr<v8::Persistent<v8::Value>> value;
   };
 }
 
 #endif