Fixed memory issues with EventHandler::TouchInfo.

Source/core/input/EventHandler.h

Index: Source/core/input/EventHandler.h
diff --git a/Source/core/input/EventHandler.h b/Source/core/input/EventHandler.h
index 5a131309cfaf097de2b1e70ea11a8e3b9d0d60a2..ce962a870f5a5106c801faf72defe4b28807f4a0 100644
--- a/Source/core/input/EventHandler.h
+++ b/Source/core/input/EventHandler.h
@@ -320,7 +320,7 @@ private:
 
     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;