Clean up and fix Utils::ToUTF8String() and Utils::ToUTF16String()

src/DefaultWebRequestWinInet.cpp

Index: src/DefaultWebRequestWinInet.cpp
===================================================================
--- a/src/DefaultWebRequestWinInet.cpp
+++ b/src/DefaultWebRequestWinInet.cpp
@@ -152,18 +152,18 @@ void ParseResponseHeaders(HINTERNET hReq
         continue;
       }
       std::wstring headerNameW = responseHeaders.substr(prevHeaderStart, headerNameEnd - prevHeaderStart);
       std::wstring headerValueW = responseHeaders.substr(headerValueStart, nextHeaderNameStart - headerValueStart);
 
       headerNameW = AdblockPlus::Utils::TrimString(headerNameW);
       headerValueW = AdblockPlus::Utils::TrimString(headerValueW);
 
-      std::string headerName = AdblockPlus::Utils::ToUTF8String(headerNameW.c_str(), headerNameW.length());
-      std::string headerValue = AdblockPlus::Utils::ToUTF8String(headerValueW.c_str(), headerValueW.length());
+      std::string headerName = AdblockPlus::Utils::ToUTF8String(headerNameW.c_str());
+      std::string headerValue = AdblockPlus::Utils::ToUTF8String(headerValueW.c_str());
 
       std::transform(headerName.begin(), headerName.end(), headerName.begin(), ::tolower);
       std::transform(headerValue.begin(), headerValue.end(), headerValue.begin(), ::tolower);
 
       result->responseHeaders.push_back(
         std::pair<std::string, std::string>(headerName, headerValue));
 
       nextHeaderNameStart++;
@@ -191,25 +191,25 @@ AdblockPlus::ServerResponse AdblockPlus:
 {
   AdblockPlus::ServerResponse result;
   result.status = NS_ERROR_FAILURE;
   result.responseStatus = 0;
 
   HRESULT hr;
   BOOL res;
 
-  std::wstring canonizedUrl = Utils::CanonizeUrl(Utils::ToUTF16String(url, url.length()));
+  std::wstring canonizedUrl = Utils::CanonizeUrl(Utils::ToUTF16String(url));
 
   std::string headersString = "";
   for (int i = 0; i < requestHeaders.size(); i++)
   {
     headersString += requestHeaders[i].first + ": ";
     headersString += requestHeaders[i].second + ";";
   }
-  std::wstring headers = Utils::ToUTF16String(headersString, headersString.length());
+  std::wstring headers = Utils::ToUTF16String(headersString);
 
   LPSTR outBuffer;
   DWORD downloadSize, downloaded;
   WinHttpHandle hSession(0), hConnect(0), hRequest(0);
 
   // Use WinHttpOpen to obtain a session handle.
   std::wstring proxyName, proxyBypass;