2011-01-28 Aparna Nandyal <aparna.nand@wipro.com>

        Reviewed by Andreas Kling.

        Setting value of m_PressedPos to make scrolling smooth

        Page scroll popup menu "Scroll here" option not working when cliking above scroll slider/handler.
        https://bugs.webkit.org/show_bug.cgi?id=51349

        The value of m_PressedPos was getting set before moveThumb() call
        in all other scenarios except when "Scroll Here" option is used.
        Hence scrolling with this option was not as expected even in cases
        where scrolling was happening. The thumb would move in unexpected
        direction. m_PressedPos is now set to pressed position so delta is
        calculated.
        Unable to write a test case as the test needs to click on "Scroll
        Here" option of context sensitive menu and QTest is unable to do it.
        Besides no new functionality introduced.

        * platform/qt/ScrollbarQt.cpp:
        (WebCore::Scrollbar::contextMenu):

Canonical link: https://commits.webkit.org/67118@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@76946 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,25 @@
+2011-01-28  Aparna Nandyal  <aparna.nand@wipro.com>
+
+        Reviewed by Andreas Kling.
+
+        Setting value of m_PressedPos to make scrolling smooth
+
+        Page scroll popup menu "Scroll here" option not working when cliking above scroll slider/handler.
+        https://bugs.webkit.org/show_bug.cgi?id=51349
+
+        The value of m_PressedPos was getting set before moveThumb() call
+        in all other scenarios except when "Scroll Here" option is used.
+        Hence scrolling with this option was not as expected even in cases
+        where scrolling was happening. The thumb would move in unexpected
+        direction. m_PressedPos is now set to pressed position so delta is
+        calculated.
+        Unable to write a test case as the test needs to click on "Scroll
+        Here" option of context sensitive menu and QTest is unable to do it.
+        Besides no new functionality introduced.
+
+        * platform/qt/ScrollbarQt.cpp:
+        (WebCore::Scrollbar::contextMenu):
+
 2011-01-28  Andrey Kosyakov  <caseq@chromium.org>
 
         Reviewed by Pavel Feldman.

Source/WebCore/platform/qt/ScrollbarQt.cpp

@@ -74,6 +74,11 @@ bool Scrollbar::contextMenu(const PlatformMouseEvent& event)
     QAction* actionSelected = menu.exec(globalPos);
 
     if (actionSelected == actScrollHere) {
+        // Set the pressed position to the middle of the thumb so that when we 
+        // do move, the delta will be from the current pixel position of the
+        // thumb to the new position
+        int position = theme()->trackPosition(this) + theme()->thumbPosition(this) + theme()->thumbLength(this) / 2;
+        setPressedPos(position); 
         const QPoint pos = convertFromContainingWindow(event.pos());
         moveThumb(horizontal ? pos.x() : pos.y());
     } else if (actionSelected == actScrollTop)