Fixed memory issues with EventHandler::TouchInfo.

Source/core/input/EventHandler.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010, 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 300 matching lines @@
     bool panScrollInProgress() const;
     void setLastKnownMousePosition(const PlatformMouseEvent&);
 
     bool shouldTopControlsConsumeScroll(FloatSize) const;
 
     // If the given element is a shadow host and its root has delegatesFocus=false flag,
     // slide focus to its inner element. Returns true if the resulting focus is different from
     // the given element.
     bool slideFocusOnShadowHostIfNecessary(const Element&);
 
     using TouchInfo = struct {

[haraken, 2015/06/22 23:40:35]

class TouchInfo {
  ALLOW_ONLY_INLINE_ALLOCATION();
public:

  DEFINE_INLINE_TRACE()
  {
    visitor->trace(touchTarget);
    visitor->trace(targetFrame);
  }

  ...;
  RefPtrWillBeMember<EventTarget> touchTarget;
  RawPtrWillBeMember<LocalFrame> targetFrame;  // BTW, is it OK to use a raw
pointer to LocalFrame?
};

[mustaq, 2015/06/23 15:25:51]

Done, but kept the pointer to LocalFrame as is because Document::frame() returns
a raw pointer.

[sof, 2015/06/23 15:57:34]

It ought to work fine as suggested; could you explain what issue you ran into?

[mustaq, 2015/06/23 16:36:27]

I kept the LocalFrame* as is because from this piece of code can't control the
life of the object accessible only through a raw pointer. Not an issue really,
just thought it doesn't make sense to use a ref-counted type here.


In case my previous comments were confusing: the oilpan compile issue I
mentioned is not related to this. It is related only to the use of
WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS.

[sof, 2015/06/23 18:52:02]

Yes, it probably isn't worth adding a RefPtr<> here now -- the above suggested
using RawPtrWillBeMember<LocalFrame>.
The trait declaration is correct, how did you work out how to address it? (Just
interested to know if we can improve error reporting for the times you need a
trait decl like this.)

[mustaq, 2015/06/24 14:47:52]

Okay, switched away from raw ptr for LocalFrame.
The compile-time error itself wasn't very useful, it was saying something around
memset() I think. I skimmed through the following page for a clue, and
WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS seemed relevant. I think adding the error
message in this page would be helpful.

https://www.chromium.org/blink/blink-gc#TOC-Collections-and-ALLOW_ONLY_INLINE...

         PlatformTouchPoint point;
-        EventTarget* touchTarget;
+        RefPtrWillBeMember<EventTarget> touchTarget;
         LocalFrame* targetFrame;
         FloatPoint adjustedPagePoint;
         FloatSize adjustedRadius;
         bool knownTarget;
         bool consumed;
     };
 
     void dispatchPointerEventsForTouchEvent(const PlatformTouchEvent&, Vector<TouchInfo>&);

[haraken, 2015/06/22 23:40:35]

You need to use WillBeHeapVector<TouchInfo>.

[mustaq, 2015/06/23 15:25:51]

Done.

     bool dispatchTouchEvents(const PlatformTouchEvent&, Vector<TouchInfo>&, bool, bool);
 
     // NOTE: If adding a new field to this class please ensure that it is
     // cleared in |EventHandler::clear()|.
 
     LocalFrame* const m_frame;
 
     bool m_mousePressed;
     bool m_capturesDragging;
     RefPtrWillBeMember<Node> m_mousePressNode;
@@ skipping 86 matching lines @@
     // scroll sequence in this frame, or any child frames. Only used
     // with ScrollCustomization. If some delta has been consumed, a
     // scroll which shouldn't propagate can't cause any element to
     // scroll other than the |m_previousGestureScrolledNode|.
     bool m_deltaConsumedForScrollSequence;
 };
 
 } // namespace blink
 
 #endif // EventHandler_h