Correctly handle touch events that contain touches not previously reported to blink

Source/core/events/EventPath.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 320 matching lines @@
         adjustedTouches.append(&touchEventContext->touches());
         adjustedTargetTouches.append(&touchEventContext->targetTouches());
         adjustedChangedTouches.append(&touchEventContext->changedTouches());
         treeScopes.append(&m_treeScopeEventContexts[i]->treeScope());
     }
 
     adjustTouchList(node, touchEvent.touches(), adjustedTouches, treeScopes);
     adjustTouchList(node, touchEvent.targetTouches(), adjustedTargetTouches, treeScopes);
     adjustTouchList(node, touchEvent.changedTouches(), adjustedChangedTouches, treeScopes);
 
+    // FIXME: Why aren't we updating the event at all? We're building up these
+    // adjusted TouchLists and throwing them away!
+

[rjkroege, 2014/05/02 20:33:50]

do the layout tests still pass if you comment them out? :-)

and if you're going to add this, maybe a tracker bug?

[Rick Byers, 2014/05/02 21:24:15]

Ah, it looks like I misunderstood the oilpannery here.  We're keeping pointers
to the TouchLists from the TouchEventContext and then mutating those lists. 
Thanks for challenging me on this.

 #ifndef NDEBUG
     for (size_t i = 0; i < m_treeScopeEventContexts.size(); ++i) {
         TreeScope& treeScope = m_treeScopeEventContexts[i]->treeScope();
         TouchEventContext* touchEventContext = m_treeScopeEventContexts[i]->touchEventContext();
         checkReachability(treeScope, touchEventContext->touches());
         checkReachability(treeScope, touchEventContext->targetTouches());
         checkReachability(treeScope, touchEventContext->changedTouches());
     }
 #endif
 }
@@ skipping 19 matching lines @@
         ASSERT(touchList.item(i)->target()->toNode()->treeScope().isInclusiveOlderSiblingShadowRootOrAncestorTreeScopeOf(treeScope));
 }
 #endif
 
 void EventPath::trace(Visitor* visitor)
 {
     visitor->trace(m_event);
 }
 
 } // namespace