Implement touch-action pan-x/pan-y handling on the main thread

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 3885 matching lines @@
 
     float magnifyDelta = exp(event.deltaY() * 0.002f);
     float newPageScaleFactor = pageScaleFactor * magnifyDelta;
 
     IntPoint anchorAfterCss(anchorBeforeDip);
     anchorAfterCss.scale(1.f / newPageScaleFactor, 1.f / newPageScaleFactor);
     page->inspectorController().requestPageScaleFactor(newPageScaleFactor, anchorBeforeCss - toIntSize(anchorAfterCss));
     return true;
 }
 
+TouchAction EventHandler::intersectTouchAction(TouchAction action1, TouchAction action2)
+{
+    if (action1 == TouchActionNone || action2 == TouchActionNone)
+        return TouchActionNone;
+    if (action1 == TouchActionAuto)
+        return action2;
+    if (action2 == TouchActionAuto)
+        return action1;
+    if (!(action1 & action2))
+        return TouchActionNone;
+    return action1 & action2;
+}
+
 TouchAction EventHandler::computeEffectiveTouchAction(const Node& node)
 {
     // Optimization to minimize risk of this new feature (behavior should be identical
     // since there's no way to get non-default touch-action values).
     if (!RuntimeEnabledFeatures::cssTouchActionEnabled())
         return TouchActionAuto;
 
     // Start by permitting all actions, then walk the block level elements from
     // the target node up to the nearest scrollable ancestor and exclude any
     // prohibited actions. For now this is trivial, but when we add more types
     // of actions it'll get a little more complex.
+    TouchAction effectiveTouchAction = TouchActionAuto;
     for (const Node* curNode = &node; curNode; curNode = NodeRenderingTraversal::parent(curNode)) {
         // The spec says only block and SVG elements get touch-action.
         // FIXME(rbyers): Add correct support for SVG, crbug.com/247396.
         if (RenderObject* renderer = curNode->renderer()) {
             if (renderer->isRenderBlockFlow()) {
-                if (renderer->style()->touchAction() == TouchActionNone)
-                    return TouchActionNone;
+                TouchAction action = renderer->style()->touchAction();
+                effectiveTouchAction = intersectTouchAction(action, effectiveTouchAction);
+                if (effectiveTouchAction == TouchActionNone)
+                    break;
             }
 
             // If we've reached an ancestor that supports a touch action, search no further.
             if (renderer->isBox() && toRenderBox(renderer)->scrollsOverflow())
                 break;
         }
     }
-    return TouchActionAuto;
+    return effectiveTouchAction;
 }
 
 void EventHandler::setLastKnownMousePosition(const PlatformMouseEvent& event)
 {
     m_mousePositionIsUnknown = false;
     m_lastKnownMousePosition = event.position();
     m_lastKnownMouseGlobalPosition = event.globalPosition();
 }
 
 bool EventHandler::passMousePressEventToSubframe(MouseEventWithHitTestResults& mev, Frame* subframe)
@@ skipping 67 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace WebCore