Make SkRWBuffer destruct safely

tests/DataRefTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkData.h"
 #include "SkDataTable.h"
 #include "SkOSFile.h"
@@ skipping 310 matching lines @@
 
     SkAutoTUnref<SkROBuffer> roBuffer(buffer.newRBufferSnapshot());
     SkROBuffer::Iter iter(roBuffer);
     REPORTER_ASSERT(r, iter.data());
     REPORTER_ASSERT(r, iter.size() == 26);
 
     // There is only one block in this buffer.
     REPORTER_ASSERT(r, !iter.next());
     REPORTER_ASSERT(r, 0 == iter.size());
 }
+
+// Tests that it is safe to destruct an SkRWBuffer without appending
+// anything to it.
+DEF_TEST(RWBuffer_noAppend, r) {
+    SkRWBuffer buffer;
+    REPORTER_ASSERT(r, 0 == buffer.size());
+}