Add DNS prefetching

Turns out we did no have DNS prefetching. It requires an extra
component. The same component can also do pre-connect, but we do not
enable that, as it requires a predictive browsing backend.

[ChangeLog][Settings] DnsPrefetchEnabled added, but disabled by default.

Change-Id: Ieb036435b9f1a72a7be302e38e89e0c347c7176b
Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io>

3 files changed, 27 insertions, 0 deletions

diff --git a/src/webengine/api/qquickwebenginesettings.cpp b/src/webengine/api/qquickwebenginesettings.cpp
index 6203f20f1..6e96e76cf 100644
--- a/src/webengine/api/qquickwebenginesettings.cpp
+++ b/src/webengine/api/qquickwebenginesettings.cpp
@@ -443,6 +443,20 @@ bool QQuickWebEngineSettings::javascriptCanPaste() const
 }
 
 /*!
+    \qmlproperty bool WebEngineSettings::dnsPrefetchEnabled
+    \since QtWebEngine 1.8
+
+    Enables speculative prefetching of DNS records for HTML links before
+    they are activated.
+
+    Disabled by default.
+*/
+bool QQuickWebEngineSettings::dnsPrefetchEnabled() const
+{
+    return d_ptr->testAttribute(WebEngineSettings::DnsPrefetchEnabled);
+}
+
+/*!
     \qmlproperty string WebEngineSettings::defaultTextEncoding
     \since QtWebEngine 1.2
 
@@ -692,6 +706,14 @@ void QQuickWebEngineSettings::setJavascriptCanPaste(bool on)
         Q_EMIT javascriptCanPasteChanged();
 }
 
+void QQuickWebEngineSettings::setDnsPrefetchEnabled(bool on)
+{
+    bool wasOn = d_ptr->testAttribute(WebEngineSettings::DnsPrefetchEnabled);
+    d_ptr->setAttribute(WebEngineSettings::DnsPrefetchEnabled, on);
+    if (wasOn != on)
+        Q_EMIT dnsPrefetchEnabledChanged();
+}
+
 void QQuickWebEngineSettings::setUnknownUrlSchemePolicy(QQuickWebEngineSettings::UnknownUrlSchemePolicy policy)
 {
     WebEngineSettings::UnknownUrlSchemePolicy oldPolicy = d_ptr->unknownUrlSchemePolicy();
diff --git a/src/webengine/api/qquickwebenginesettings_p.h b/src/webengine/api/qquickwebenginesettings_p.h
index ca583379d..179416b54 100644
--- a/src/webengine/api/qquickwebenginesettings_p.h
+++ b/src/webengine/api/qquickwebenginesettings_p.h
@@ -92,6 +92,7 @@ class Q_WEBENGINE_PRIVATE_EXPORT QQuickWebEngineSettings : public QObject {
     Q_PROPERTY(bool playbackRequiresUserGesture READ playbackRequiresUserGesture WRITE setPlaybackRequiresUserGesture NOTIFY playbackRequiresUserGestureChanged REVISION 6 FINAL)
     Q_PROPERTY(bool webRTCPublicInterfacesOnly READ webRTCPublicInterfacesOnly WRITE setWebRTCPublicInterfacesOnly NOTIFY webRTCPublicInterfacesOnlyChanged REVISION 6 FINAL)
     Q_PROPERTY(bool javascriptCanPaste READ javascriptCanPaste WRITE setJavascriptCanPaste NOTIFY javascriptCanPasteChanged REVISION 6 FINAL)
+    Q_PROPERTY(bool dnsPrefetchEnabled READ dnsPrefetchEnabled WRITE setDnsPrefetchEnabled NOTIFY dnsPrefetchEnabledChanged REVISION 7 FINAL)
 
 public:
     enum UnknownUrlSchemePolicy {
@@ -133,6 +134,7 @@ public:
     bool playbackRequiresUserGesture() const;
     bool webRTCPublicInterfacesOnly() const;
     bool javascriptCanPaste() const;
+    bool dnsPrefetchEnabled() const;
 
     void setAutoLoadImages(bool on);
     void setJavascriptEnabled(bool on);
@@ -163,6 +165,7 @@ public:
     void setPlaybackRequiresUserGesture(bool on);
     void setWebRTCPublicInterfacesOnly(bool on);
     void setJavascriptCanPaste(bool on);
+    void setDnsPrefetchEnabled(bool on);
 
 signals:
     void autoLoadImagesChanged();
@@ -194,6 +197,7 @@ signals:
     Q_REVISION(6) void playbackRequiresUserGestureChanged();
     Q_REVISION(6) void webRTCPublicInterfacesOnlyChanged();
     Q_REVISION(6) void javascriptCanPasteChanged();
+    Q_REVISION(7) void dnsPrefetchEnabledChanged();
 
 private:
     explicit QQuickWebEngineSettings(QQuickWebEngineSettings *parentSettings = 0);
diff --git a/src/webengine/plugin/plugin.cpp b/src/webengine/plugin/plugin.cpp
index d81b797fc..545f17f82 100644
--- a/src/webengine/plugin/plugin.cpp
+++ b/src/webengine/plugin/plugin.cpp
@@ -119,6 +119,7 @@ public:
         qmlRegisterUncreatableType<QQuickWebEngineSettings, 4>(uri, 1, 5, "WebEngineSettings", tr("Cannot create a separate instance of WebEngineSettings"));
         qmlRegisterUncreatableType<QQuickWebEngineSettings, 5>(uri, 1, 6, "WebEngineSettings", tr("Cannot create a separate instance of WebEngineSettings"));
         qmlRegisterUncreatableType<QQuickWebEngineSettings, 6>(uri, 1, 7, "WebEngineSettings", tr("Cannot create a separate instance of WebEngineSettings"));
+        qmlRegisterUncreatableType<QQuickWebEngineSettings, 7>(uri, 1, 8, "WebEngineSettings", tr("Cannot create a separate instance of WebEngineSettings"));
         qmlRegisterSingletonType<QQuickWebEngineSingleton>(uri, 1, 1, "WebEngine", webEngineSingletonProvider);
         qmlRegisterUncreatableType<QQuickWebEngineHistory>(uri, 1, 1, "NavigationHistory",
             tr("Cannot create a separate instance of NavigationHistory"));