Hide sidebar when a web element goes to full screen.

- Closes #2423

src/lib/app/browserwindow.cpp

@@ -800,10 +800,17 @@ void BrowserWindow::toggleFullScreen()
         showFullScreen();
 }
 
-void BrowserWindow::enterHtmlFullScreen()
+void BrowserWindow::toggleHtmlFullScreen(bool enable)
 {
-    showFullScreen();
-    m_isHtmlFullScreen = true;
+    if (enable)
+        showFullScreen();
+    else
+        showNormal();
+
+    if (m_sideBar)
+        m_sideBar.data()->setHidden(enable);
+
+    m_isHtmlFullScreen = enable;
 }
 
 void BrowserWindow::showWebInspector()

src/lib/app/browserwindow.h

@@ -131,7 +131,7 @@ public slots:
     void toggleTabsOnTop(bool enable);
 
     void toggleFullScreen();
-    void enterHtmlFullScreen();
+    void toggleHtmlFullScreen(bool enable);
 
     void loadActionUrl(QObject* obj = 0);
     void loadActionUrlInNewTab(QObject* obj = 0);

src/lib/webtab/tabbedwebview.cpp

@@ -1,6 +1,6 @@
 /* ============================================================
 * QupZilla - WebKit based browser
-* Copyright (C) 2010-2016 David Rosca <nowrep@gmail.com>
+* Copyright (C) 2010-2017 David Rosca <nowrep@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -182,10 +182,7 @@ void TabbedWebView::requestFullScreen(bool enable)
     if (!m_window)
         return;
 
-    if (enable)
-        m_window->enterHtmlFullScreen();
-    else
-        m_window->showNormal();
+    m_window->toggleHtmlFullScreen(enable);
 }
 
 void TabbedWebView::setAsCurrentTab()