Initial scroll-blocks-on compositor integration

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 494 matching lines @@
 {
     const LocalFrame* frame = document.frame();
 
     RefPtr<RenderStyle> documentStyle = RenderStyle::create();
     documentStyle->setDisplay(BLOCK);
     documentStyle->setRTLOrdering(document.visuallyOrdered() ? VisualOrder : LogicalOrder);
     documentStyle->setZoom(frame && !document.printing() ? frame->pageZoomFactor() : 1);
     documentStyle->setLocale(document.contentLanguage());
     documentStyle->setZIndex(0);
     documentStyle->setUserModify(document.inDesignMode() ? READ_WRITE : READ_ONLY);
+    documentStyle->setScrollBlocksOn(WebScrollBlocksOnStartTouch | WebScrollBlocksOnWheelEvent);

[skobes, 2015/01/07 18:49:24]

If you have this default in the UA stylesheet (Source/core/css/html.css), why do
you also need to set it here?

[Rick Byers, 2015/01/08 21:08:11]

This gets applied to the RenderView and is designed to work with the logic in
Document::inheritHtmlAndBodyElementStyles.  I.e. we'll create a new RenderStyle
object for RenderView if the value we'd propagate from html is different from
what we've already got on renderview.  I don't want to force us to go down the
new RenderStyle path 100% of the time now.

But this whole renderview vs. html style thing is getting pretty unwieldy, and
I'm having some problems caused by the user agent stylesheet (creating the
RenderLayer can change the stacking order - eg. cases like an SVG document with
embedded html documents).  Really what I want is a default style on the
RenderView only, with the user still being able to override it by setting a
style on html.  One way I could support that without relying on a user agent
stylesheet is by defining a new value 'auto' and making that the default value. 
Then when someone does 'html { scroll-blocks-on: none; }' I can still
differentiate that from the default case.  I'll try whipping up a version of the
CL with that design and we can see if we like it better.

 
     document.setupFontBuilder(documentStyle.get());
 
     return documentStyle.release();
 }
 
 void StyleResolver::adjustRenderStyle(StyleResolverState& state, Element* element)
 {
     StyleAdjuster adjuster(document().inQuirksMode());
     adjuster.adjustRenderStyle(state.style(), state.parentStyle(), element, state.cachedUAStyle());
@@ skipping 1078 matching lines @@
     visitor->trace(m_uncommonAttributeRuleSet);
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingRules);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 #endif
 }
 
 } // namespace blink