Simple browser example: create off-the-record profile in a lazy manner

Do not create multiple profiles immediately on start. Allows to start
and run browser with default profile with 'single-process' flag.

Change-Id: Idea7da8167152f718a3c2d4086ad4216d8e1b722
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>

3 files changed, 24 insertions, 14 deletions

diff --git a/examples/webenginewidgets/simplebrowser/browser.cpp b/examples/webenginewidgets/simplebrowser/browser.cpp
index 5c6dbd35e..68458b2a4 100644
--- a/examples/webenginewidgets/simplebrowser/browser.cpp
+++ b/examples/webenginewidgets/simplebrowser/browser.cpp
@@ -51,8 +51,6 @@
 #include "browser.h"
 #include "browserwindow.h"
 
-#include <QWebEngineProfile>
-
 Browser::Browser()
 {
     // Quit application if the download manager window is the only remaining window
@@ -61,14 +59,17 @@ Browser::Browser()
     QObject::connect(
         QWebEngineProfile::defaultProfile(), &QWebEngineProfile::downloadRequested,
         &m_downloadManagerWidget, &DownloadManagerWidget::downloadRequested);
-    QObject::connect(
-        &m_otrProfile, &QWebEngineProfile::downloadRequested,
-        &m_downloadManagerWidget, &DownloadManagerWidget::downloadRequested);
 }
 
 BrowserWindow *Browser::createWindow(bool offTheRecord)
 {
-    auto profile = offTheRecord ? &m_otrProfile : QWebEngineProfile::defaultProfile();
+    if (offTheRecord && !m_otrProfile) {
+        m_otrProfile.reset(new QWebEngineProfile);
+        QObject::connect(
+            m_otrProfile.get(), &QWebEngineProfile::downloadRequested,
+            &m_downloadManagerWidget, &DownloadManagerWidget::downloadRequested);
+    }
+    auto profile = offTheRecord ? m_otrProfile.get() : QWebEngineProfile::defaultProfile();
     auto mainWindow = new BrowserWindow(this, profile, false);
     m_windows.append(mainWindow);
     QObject::connect(mainWindow, &QObject::destroyed, [this, mainWindow]() {
diff --git a/examples/webenginewidgets/simplebrowser/browser.h b/examples/webenginewidgets/simplebrowser/browser.h
index fbc8465d2..4c17121df 100644
--- a/examples/webenginewidgets/simplebrowser/browser.h
+++ b/examples/webenginewidgets/simplebrowser/browser.h
@@ -73,6 +73,6 @@ public:
 private:
     QVector<BrowserWindow*> m_windows;
     DownloadManagerWidget m_downloadManagerWidget;
-    QWebEngineProfile m_otrProfile;
+    QScopedPointer<QWebEngineProfile> m_otrProfile;
 };
 #endif // BROWSER_H
diff --git a/examples/webenginewidgets/simplebrowser/doc/src/simplebrowser.qdoc b/examples/webenginewidgets/simplebrowser/doc/src/simplebrowser.qdoc
index b5ad13626..251ca5ad8 100644
--- a/examples/webenginewidgets/simplebrowser/doc/src/simplebrowser.qdoc
+++ b/examples/webenginewidgets/simplebrowser/doc/src/simplebrowser.qdoc
@@ -270,7 +270,7 @@
     Implementing private browsing is quite easy using \QWE. All one has
     to do is to create a new \l{QWebEngineProfile} and use it in the
     \l{QWebEnginePage} instead of the default profile. In the example this new
-    profile is created and owned by the \c Browser object:
+    profile is owned by the \c Browser object:
 
     \quotefromfile webenginewidgets/simplebrowser/browser.h
     \skipto /^class Browser$/
@@ -285,15 +285,24 @@
     \printline m_otrProfile
     \printline /^\};$/
 
-    The default constructor for \l{QWebEngineProfile} already puts it in
-    \e{off-the-record} mode. All that is left to do is to pass the appropriate
-    profile down to the appropriate \l QWebEnginePage objects. The \c Browser
-    object will hand to each new \c BrowserWindow either the global default
-    profile (see \l{QWebEngineProfile::defaultProfile}) or its own
-    off-the-record profile:
+    Required profile for \e{private browsing} is created together with its
+    first window. The default constructor for \l{QWebEngineProfile} already
+    puts it in \e{off-the-record} mode.
 
     \quotefromfile webenginewidgets/simplebrowser/browser.cpp
+
     \skipto Browser::createWindow
+    \printuntil m_otrProfile.reset
+    \dots
+
+    All that is left to do is to pass the appropriate profile down to the
+    appropriate \l QWebEnginePage objects. The \c Browser object will hand to
+    each new \c BrowserWindow either the global default profile
+    (see \l{QWebEngineProfile::defaultProfile}) or one shared
+    \e{off-the-record} profile instance:
+
+    \dots
+    \skipto m_otrProfile.get
     \printuntil mainWindow = new BrowserWindow
     \skipto return mainWindow
     \printuntil /^\}/