Oilpan: move editing objects to the heap.

Source/core/editing/VisibleSelection.h

Index: Source/core/editing/VisibleSelection.h
diff --git a/Source/core/editing/VisibleSelection.h b/Source/core/editing/VisibleSelection.h
index c14630c15d700258279bc14bf5c7d10716c4e681..db71261e143aa7a270ecc9e711bf2ba0a4e93818 100644
--- a/Source/core/editing/VisibleSelection.h
+++ b/Source/core/editing/VisibleSelection.h
@@ -39,6 +39,7 @@ const EAffinity SEL_DEFAULT_AFFINITY = DOWNSTREAM;
 enum SelectionDirection { DirectionForward, DirectionBackward, DirectionRight, DirectionLeft };
 
 class VisibleSelection {
+    DISALLOW_ALLOCATION();
 public:
     VisibleSelection();
 
@@ -128,6 +129,8 @@ public:
     void clearChangeObserver();
     void didChange(); // Fire the change observer, if any.
 
+    void trace(Visitor*);
+
 #ifndef NDEBUG
     void debugPosition() const;
     void formatForDebugger(char* buffer, unsigned length) const;
@@ -156,6 +159,8 @@ private:
 
     EAffinity m_affinity;           // the upstream/downstream affinity of the caret
 
+    // Oilpan: this reference has a lifetime that is at least as long
+    // as this object.
     ChangeObserver* m_changeObserver;

[haraken, 2014/05/29 01:14:15]

I agree that no weak processing is needed for the observer.

Given that the only derived class of ChangeObserver is FrameSelection (which is
on heap), can we change this to a Member and trace it? It's not really nice to
leave a raw pointer in on-heap objects.

[sof, 2014/05/29 10:03:53]

Done, made ChangeObserver a GC mixin.

 
     // these are cached, can be recalculated by validate()