Let additional mouse buttons trigger history navigation

This is consistent with a recent change in Dolphin and with what browsers have been doing for a long time.

REVIEW: 105440
DIGEST:

part.cpp

@@ -2561,9 +2561,11 @@ void Part::unsetDummyMode()
     // add back and next in history
     m_historyBack = KStandardAction::documentBack( this, SLOT(slotHistoryBack()), actionCollection() );
     m_historyBack->setWhatsThis( i18n( "Go to the place you were before" ) );
+    connect(m_pageView, SIGNAL(mouseBackButtonClick()), m_historyBack, SLOT(trigger()));
 
     m_historyNext = KStandardAction::documentForward( this, SLOT(slotHistoryNext()), actionCollection());
     m_historyNext->setWhatsThis( i18n( "Go to the place you were after" ) );
+    connect(m_pageView, SIGNAL(mouseForwardButtonClick()), m_historyNext, SLOT(trigger()));
 
     m_pageView->setupActions( actionCollection() );
 

ui/pageview.cpp

@@ -1949,6 +1949,18 @@ void PageView::mousePressEvent( QMouseEvent * e )
         return;
     }
 
+    // trigger history navigation for additional mouse buttons
+    if ( e->button() == Qt::XButton1 )
+    {
+        emit mouseBackButtonClick();
+        return;
+    }
+    if ( e->button() == Qt::XButton2 )
+    {
+        emit mouseForwardButtonClick();
+        return;
+    }
+
     // update press / 'start drag' mouse position
     d->mousePressPos = e->globalPos();
 

ui/pageview.h

@@ -131,6 +131,8 @@ Q_OBJECT
     signals:
         void urlDropped( const KUrl& );
         void rightClick( const Okular::Page *, const QPoint & );
+        void mouseBackButtonClick();
+        void mouseForwardButtonClick();
 
     protected:
         void resizeEvent( QResizeEvent* );