Oilpan: Remove ref counting from EventTarget and all uses of Pass/RefPtr<EventTarget>.

Source/core/page/EventHandler.cpp

Index: Source/core/page/EventHandler.cpp
diff --git a/Source/core/page/EventHandler.cpp b/Source/core/page/EventHandler.cpp
index 0bc19a21a3ae478648db1867035abbfdf6b072c4..e9c3e79cd7783117487348721ef80b61aba23bc1 100644
--- a/Source/core/page/EventHandler.cpp
+++ b/Source/core/page/EventHandler.cpp
@@ -3479,7 +3479,7 @@ bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
     TargetTouchesHeapMap touchesByTarget;
 
     // Array of touches per state, used to assemble the 'changedTouches' list.
-    typedef HashSet<RefPtr<EventTarget> > EventTargetSet;
+    typedef WillBeHeapHashSet<RefPtrWillBeMember<EventTarget> > EventTargetSet;
     struct {
         // The touches corresponding to the particular change state this struct
         // instance represents.
@@ -3492,7 +3492,7 @@ bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
         const PlatformTouchPoint& point = points[i];
         LayoutPoint pagePoint = documentPointForWindowPoint(m_frame, point.pos());
         PlatformTouchPoint::State pointState = point.state();
-        RefPtr<EventTarget> touchTarget;
+        RefPtrWillBeRawPtr<EventTarget> touchTarget = nullptr;
 
         if (pointState == PlatformTouchPoint::TouchReleased || pointState == PlatformTouchPoint::TouchCancelled) {
             // The target should be the original target for this touch, so get