Making VisibleSelection operator== take base and extent into account.

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 75856ea84e53dc33c3ed5fbc93a903cfc1826c55..5fe553b3bc3fc45f213604350119147950c95104 100644
--- a/Source/core/editing/VisibleSelection.h
+++ b/Source/core/editing/VisibleSelection.h
@@ -182,8 +182,11 @@ private:
 
 inline bool operator==(const VisibleSelection& a, const VisibleSelection& b)
 {
-    return a.start() == b.start() && a.end() == b.end() && a.affinity() == b.affinity() && a.isBaseFirst() == b.isBaseFirst()
-        && a.isDirectional() == b.isDirectional();
+    if (a.isNone())
+        return b.isNone();

[yosin_UTC9, 2015/04/17 04:15:58]

We need to check affinity() and isDirectional() even if selection is none.
This is the reason why editing/deleting/delete-cell-contents-win.html failed on
Mac.

The root cause is found in FrameSelection::setSelection()

void FrameSelection::setSelection() {
...
  VisibleSelection s = validateSelection(newSelection);
    if (shouldAlwaysUseDirectionalSelection(m_frame))
        s.setIsDirectional(true);  /// Set isDirectional regardless selection
type, e.g. including selection is empty
...
   if (m_selection == s) {  // Check new selection is different from current
selection
     ...
     return;
   }
...
  // Log selection change event in test_runner.
  m_frame->editor().respondToChangedSelection(oldSelection, options);
...

+
+    return a.start() == b.start() && a.end() == b.end() && a.affinity() == b.affinity()
+        && a.isDirectional() == b.isDirectional() && a.base() == b.base() && a.extent() == b.extent();
 }
 
 inline bool operator!=(const VisibleSelection& a, const VisibleSelection& b)