Test abandoning GL context in dm/nanobench.

bench/nanobench.cpp

 /*
  * 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 <ctype.h>
 
 #include "Benchmark.h"
@@ skipping 459 matching lines @@
                         , stddev_percent
                         , stats.plot.c_str()
                         , config
                         , bench->getName()
                         );
             }
         }
         targets.deleteAll();
 
     #if SK_SUPPORT_GPU
-        if (FLAGS_resetGpuContext) {
+        if (FLAGS_abandonGpuContext) {
+            gGrFactory.abandonContexts();
+        }
+        if (FLAGS_resetGpuContext || FLAGS_abandonGpuContext) {
             gGrFactory.destroyContexts();
         }
     #endif
     }
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return nanobench_main();
 }
 #endif