destroyContexts after each bench instead of before

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 201 matching lines @@
             t->surface.reset(code);                                        \
             targets->push(t);                                              \
         }
     if (FLAGS_cpu) {
         CPU_TARGET(nonrendering, kNonRendering_Backend, NULL)
         CPU_TARGET(8888, kRaster_Backend, SkSurface::NewRaster(_8888))
         CPU_TARGET(565,  kRaster_Backend, SkSurface::NewRaster(_565))
     }
 
 #if SK_SUPPORT_GPU
-    if (FLAGS_resetGpuContext) {
-        gGrFactory.destroyContexts();
-    }
 
     #define GPU_TARGET(config, ctxType, info, samples)                                            \
         if (Target* t = is_enabled(bench, Benchmark::kGPU_Backend, #config)) {                    \
             t->surface.reset(SkSurface::NewRenderTarget(gGrFactory.get(ctxType), info, samples)); \
             t->gl = gGrFactory.getGLContext(ctxType);                                             \
             targets->push(t);                                                                     \
         }
     if (FLAGS_gpu) {
         GPU_TARGET(gpu,      GrContextFactory::kNative_GLContextType, _8888, 0)
         GPU_TARGET(msaa4,    GrContextFactory::kNative_GLContextType, _8888, 4)
@@ skipping 118 matching lines @@
                         , humanize(stats.mean).c_str()
                         , humanize(stats.max).c_str()
                         , stddev_percent
                         , stats.plot.c_str()
                         , config
                         , bench->getName()
                         );
             }
         }
         targets.deleteAll();
+
+    #if SK_SUPPORT_GPU
+        if (FLAGS_resetGpuContext) {
+            gGrFactory.destroyContexts();
+        }
+    #endif
     }
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif