Fix Vulkan Build in Android

src/gpu/vk/GrVkGpu.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 "GrVkGpu.h"
 
 #include "GrContextOptions.h"
@@ skipping 64 matching lines @@
     }
 
     return new GrVkGpu(context, options, vkBackendContext);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 GrVkGpu::GrVkGpu(GrContext* context, const GrContextOptions& options,
                  const GrVkBackendContext* backendCtx)
     : INHERITED(context)
+#ifdef ENABLE_VK_LAYERS
     , fVkInstance(backendCtx->fInstance)
+#endif
     , fDevice(backendCtx->fDevice)
     , fQueue(backendCtx->fQueue)
     , fResourceProvider(this) {
     fBackendContext.reset(backendCtx);
 
 #ifdef ENABLE_VK_LAYERS
     if (backendCtx->fExtensions & kEXT_debug_report_GrVkExtensionFlag) {
         // Setup callback creation information
         VkDebugReportCallbackCreateInfoEXT callbackCreateInfo;
         callbackCreateInfo.sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT;
@@ skipping 1608 matching lines @@
     aglSwapBuffers(aglGetCurrentContext());
     int set_a_break_pt_here = 9;
     aglSwapBuffers(aglGetCurrentContext());
 #elif defined(SK_BUILD_FOR_WIN32)
     SwapBuf();
     int set_a_break_pt_here = 9;
     SwapBuf();
 #endif
 #endif
 }