Retract GrRenderTarget from GrTestTarget

bench/GLBench.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GLBench.h"
 
 #if SK_SUPPORT_GPU
+#include "GrGpu.h"
 #include "GrTest.h"
+#include "gl/GrGLContext.h"
 #include <stdio.h>
 
 const GrGLContext* GLBench::getGLContext(SkCanvas* canvas) {
     // This bench exclusively tests GL calls directly
     if (nullptr == canvas->getGrContext()) {
         return nullptr;
     }
     GrContext* context = canvas->getGrContext();
     GrGpu* gpu = context->getGpu();
     if (!gpu) {
@@ skipping 142 matching lines @@
     bm.setPixels(readback.get());
 
     if (!SkImageEncoder::EncodeFile(filename, bm, SkImageEncoder::kPNG_Type, 100)) {
         SkDebugf("------ failed to encode %s\n", filename);
         remove(filename);   // remove any partial file
         return;
     }
 }
 
 #endif