Replace various ScrollableArea scroll methods with setScrollPosition

Source/core/frame/LocalFrame.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Simon Hausmann <hausmann@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  *                     2001 George Staikos <staikos@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 502 matching lines @@
     if (document->isSVGDocument()) {
         if (!document->accessSVGExtensions().zoomAndPanEnabled())
             return;
     }
 
     if (m_pageZoomFactor != pageZoomFactor) {
         if (FrameView* view = this->view()) {
             // Update the scroll position when doing a full page zoom, so the content stays in relatively the same position.
             LayoutPoint scrollPosition = view->scrollPosition();
             float percentDifference = (pageZoomFactor / m_pageZoomFactor);
-            view->setScrollPosition(DoublePoint(scrollPosition.x() * percentDifference, scrollPosition.y() * percentDifference));
+            view->setScrollPosition(
+                DoublePoint(scrollPosition.x() * percentDifference, scrollPosition.y() * percentDifference),
+                ProgrammaticScroll);

[skobes, 2015/06/04 23:35:47]

Why is this a programmatic scroll?  It seems conceptually similar to pinch zoom.

[bokan, 2015/06/05 15:15:23]

I guess it could be argued either way, my view is this (and pinch-zoom actually)
is the browser keeping the view anchored so it's not really the user scrolling.
In this case more so, the user action doesn't really relate to scrolling. i.e.
If the user changes the zoom level, we shouldn't set the FrameView's
scrolledByUser and prevent resetting the scroll offset on a history navigation.

It does fall into an "in between" type though, maybe we want a separate type?
AnchorScroll or something like that? I was already thinking about that since
we'll want to do some special behavior for scrolling in RootFrameViewport if
it's from a pinch-zoom gesture. If you don't feel strongly though I'd leave that
for the RootFrameViewport/pinchzoom patch.

[skobes, 2015/06/05 15:53:57]

It would be nice to have a comment on the ScrollType enum that documents what
the intent and consequences of each value are.  Can be a separate patch.

[bokan, 2015/06/05 20:35:35]

Good point, I'll add it once the rest of my patches land and it's more clear
what the differences are.

         }
     }
 
     m_pageZoomFactor = pageZoomFactor;
     m_textZoomFactor = textZoomFactor;
 
     for (RefPtrWillBeRawPtr<Frame> child = tree().firstChild(); child; child = child->tree().nextSibling()) {
         if (child->isLocalFrame())
             toLocalFrame(child.get())->setPageAndTextZoomFactors(m_pageZoomFactor, m_textZoomFactor);
     }
@@ skipping 278 matching lines @@
     , m_textZoomFactor(parentTextZoomFactor(this))
     , m_inViewSourceMode(false)
 {
     if (isLocalRoot())
         m_instrumentingAgents = InstrumentingAgents::create();
     else
         m_instrumentingAgents = localFrameRoot()->m_instrumentingAgents;
 }
 
 } // namespace blink