Issue 5013 - Use const JsValue and pass reference where applicable

test/JsValue.cpp

 /*
  * 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 138 matching lines @@
   ASSERT_TRUE(value->IsObject());
   ASSERT_FALSE(value->IsArray());
   ASSERT_FALSE(value->IsFunction());
   ASSERT_EQ("foo", value->AsString());
   ASSERT_EQ(123, value->AsInt());
   ASSERT_TRUE(value->AsBool());
   ASSERT_ANY_THROW(value->AsList());
   ASSERT_EQ(2, value->GetProperty("x")->AsInt());
   value->SetProperty("x", 12);
   ASSERT_EQ(12, value->GetProperty("x")->AsInt());
-  value->SetProperty("x", jsEngine->NewValue(15));
+  value->SetProperty("x", *jsEngine->NewValue(15));
   ASSERT_EQ(15, value->GetProperty("x")->AsInt());
   ASSERT_EQ("Foo", value->GetClass());
   ASSERT_EQ(3u, value->GetOwnPropertyNames().size());
   ASSERT_ANY_THROW(value->Call());
 }
 
 TEST_F(JsValueTest, ArrayValue)
 {
   AdblockPlus::JsValuePtr value = jsEngine->Evaluate("[5,8,12]");
   ASSERT_FALSE(value->IsUndefined());
@@ skipping 46 matching lines @@
   const std::string source("\
     function Foo() {\
       this.toString = function() {throw 'test1';};\
       this.valueOf = function() {throw 'test2';};\
     };\
     new Foo()");
   AdblockPlus::JsValuePtr value = jsEngine->Evaluate(source);
   ASSERT_EQ("", value->AsString());
   ASSERT_EQ(0, value->AsInt());
 }