Fix Vulkan tests after GrContextFactory move to sk_gpu_test

tests/VkClearTests.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.
  */
 
 // This is a GPU-backend specific test. It relies on static intializers to work
 
 #include "SkTypes.h"
 
 #if SK_SUPPORT_GPU && SK_ALLOW_STATIC_GLOBAL_INITIALIZERS && defined(SK_VULKAN)
 
 #include "GrContextFactory.h"
 #include "GrTest.h"
 #include "Test.h"
 #include "vk/GrVkGpu.h"
 
+using sk_gpu_test::GrContextFactory;
+
 bool does_full_buffer_contain_correct_color(GrColor* buffer,
                                             GrColor clearColor,
                                             GrPixelConfig config,
                                             int width,
                                             int height) {
     GrColor matchColor;
     if (kRGBA_8888_GrPixelConfig == config) {
         matchColor = clearColor;
     } else if (kBGRA_8888_GrPixelConfig) {
         // Hack to flip the R, B componets in the GrColor so that the comparrison will work below
@@ skipping 179 matching lines @@
             basic_clear_test(reporter, context, kRGBA_8888_GrPixelConfig);
             basic_clear_test(reporter, context, kBGRA_8888_GrPixelConfig);
             sub_clear_test(reporter, context, kRGBA_8888_GrPixelConfig);
             sub_clear_test(reporter, context, kBGRA_8888_GrPixelConfig);
         }
 
     }
 }
 
 #endif