Alias deref -> unref. This allows Skia objects to be held by WTF::RefPtr

smart pointers without need for another smart pointer type.

Note that the semantics of SkRefCnt match those WTF expects. In
particular, newly created objects have refcount 1 and objects are
deallocated at refcount 0.

This seems like a better fit than the AddRef/Release alises which exist
for scoped_ptr (but seem unused).

BUG=254509
R=reed@google.com

Author: jbroman@chromium.org

Review URL: https://chromiumcodereview.appspot.com/17880003

git-svn-id: http://skia.googlecode.com/svn/trunk@9784 2bbb7eff-a529-9590-31e7-b0007b416f81

include/core/SkRefCnt.h

@@ -81,6 +81,11 @@ public:
      */
     void Release() { this->unref(); }
 
+    /**
+     * Alias for unref(), for compatibility with WTF::RefPtr.
+     */
+    void deref() { this->unref(); }
+
 protected:
     /**
      *  Allow subclasses to call this if they've overridden internal_dispose