Fix WebEngineContext on Windows

AppendSwitchASCII won't accept WChars, it would need WideToASCII
conversion. But on OS_WIN AppendSwitchASCII method only wraps
parameters for AppendSwitchNative with ASCIIToWide.
Doing ASCIIToWide(WideToASCII()) not seems to be a useful idea,
so we should call directly AppendSwitchNative on Windows.
See chromium/base/command_line.cc.

Change-Id: I9733993840ddaef2dbb3176135977c39a967e381
Reviewed-by: Andras Becsi <andras.becsi@digia.com>

src/core/web_engine_context.cpp

@@ -131,7 +131,11 @@ WebEngineContext::WebEngineContext(WebContentsAdapterClient::RenderingMode rende
 
     CommandLine* parsedCommandLine = CommandLine::ForCurrentProcess();
     parsedCommandLine->AppendSwitchASCII(switches::kUserAgent, webkit_glue::BuildUserAgentFromProduct("QtWebEngine/0.1"));
+#if defined(OS_WIN)
+    parsedCommandLine->AppendSwitchNative(switches::kBrowserSubprocessPath,WebEngineLibraryInfo::subProcessPath().value().c_str());
+#else
     parsedCommandLine->AppendSwitchASCII(switches::kBrowserSubprocessPath, WebEngineLibraryInfo::subProcessPath().value().c_str());
+#endif
     parsedCommandLine->AppendSwitch(switches::kNoSandbox);
     parsedCommandLine->AppendSwitch(switches::kDisablePlugins);