Render web tooltips in browser source Interact using Qt

This code was originally intended for Browser Docks, but CEF is
supposed to handle it internally. OnTooltip never triggers outside of
OSR. https://bitbucket.org/chromiumembedded/cef/issues/783/

Per documentation for this function, when using OSR it's up to the
parent app (ie. OBS) to render a tooltip.

browser-client.cpp

@@ -23,6 +23,9 @@
 #include <obs-frontend-api.h>
 #include <obs.hpp>
 #include <util/platform.h>
+#include <QApplication>
+#include <QThread>
+#include <QToolTip>
 
 using namespace json11;
 
@@ -172,6 +175,16 @@ bool BrowserClient::GetViewRect(
 #endif
 }
 
+bool BrowserClient::OnTooltip(CefRefPtr<CefBrowser>, CefString &text)
+{
+	std::string str_text = text;
+	QMetaObject::invokeMethod(
+		QCoreApplication::instance()->thread(), [str_text]() {
+			QToolTip::showText(QCursor::pos(), str_text.c_str());
+		});
+	return true;
+}
+
 void BrowserClient::OnPaint(CefRefPtr<CefBrowser>, PaintElementType type,
 			    const RectList &, const void *buffer, int width,
 			    int height)

browser-client.hpp

@@ -97,6 +97,8 @@ class BrowserClient : public CefClient,
 				      const CefString &message,
 				      const CefString &source,
 				      int line) override;
+	virtual bool OnTooltip(CefRefPtr<CefBrowser> browser,
+			       CefString &text) override;
 
 	/* CefLifeSpanHandler */
 	virtual bool