Rename SkDrawPictureCallback to SkAbortCallback

include/core/SkAbortCallback.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTypes.h"
+
+#ifndef SkAbortCallback_DEFINED
+#define SkAbortCallback_DEFINED
+
+/**
+*  Subclasses of this can be passed to SkPicture::playback(). During the playback
+*  of the picture, this callback will periodically be invoked. If its
+*  abort() returns true, then picture playback will be interrupted.
+*
+*  The resulting drawing is undefined, as there is no guarantee how often the
+*  callback will be invoked. If the abort happens inside some level of nested
+*  calls to save(), restore will automatically be called to return the state
+*  to the same level it was before the playback call was made.
+*/
+class SK_API SkAbortCallback {
+public:
+    SkAbortCallback() {}
+    virtual ~SkAbortCallback() {}
+
+    virtual bool abort() = 0;
+};
+
+#endif // SkAbortCallback_DEFINED