Move SkGLContext and some GrGLInterface implementations to skgputest module

tests/RectangleTextureTest.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 "Test.h"
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "GrDrawContext.h"
 #include "gl/GrGLGpu.h"
 #include "gl/GrGLUtil.h"
-#include "gl/SkGLContext.h"
+#include "gl/GLContext.h"
 
 static void test_read_pixels(skiatest::Reporter* reporter, GrContext* context,
                              GrTexture* rectangleTexture, uint32_t expectedPixelValues[]) {
     int pixelCnt = rectangleTexture->width() * rectangleTexture->height();
     SkAutoTMalloc<uint32_t> pixels(pixelCnt);
     memset(pixels.get(), 0, sizeof(uint32_t)*pixelCnt);
     bool read = rectangleTexture->readPixels(0, 0, rectangleTexture->width(),
                                             rectangleTexture->height(), kRGBA_8888_GrPixelConfig,
                                             pixels.get());
     if (!read) {
@@ skipping 173 matching lines @@
 
         test_write_pixels(reporter, context, rectangleTexture);
 
         test_clear(reporter, context, rectangleTexture);
 
         GR_GL_CALL(glContext->gl(), DeleteTextures(1, &rectTexID));
     }
 }
 
 #endif