Fix vulkan ImageView swizzling to match spec

src/gpu/vk/GrVkImageView.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "GrVkImageView.h"
 #include "GrVkGpu.h"
 #include "GrVkUtil.h"
 
 const GrVkImageView* GrVkImageView::Create(const GrVkGpu* gpu, VkImage image, VkFormat format,
                                            Type viewType, uint32_t miplevels) {
     VkImageView imageView;
 
     // Create the VkImageView
     VkImageViewCreateInfo viewInfo = {
         VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO,               // sType
         NULL,                                                   // pNext
         0,                                                      // flags
         image,                                                  // image
         VK_IMAGE_VIEW_TYPE_2D,                                  // viewType
         format,                                                 // format
-        { VK_COMPONENT_SWIZZLE_R, VK_COMPONENT_SWIZZLE_G,
-          VK_COMPONENT_SWIZZLE_B, VK_COMPONENT_SWIZZLE_A },     // components
+        { VK_COMPONENT_SWIZZLE_IDENTITY,
+          VK_COMPONENT_SWIZZLE_IDENTITY,
+          VK_COMPONENT_SWIZZLE_IDENTITY,
+          VK_COMPONENT_SWIZZLE_IDENTITY },                      // components
         { VK_IMAGE_ASPECT_COLOR_BIT, 0, miplevels, 0, 1 },      // subresourceRange
     };
     if (kStencil_Type == viewType) {
-        viewInfo.components.r = VK_COMPONENT_SWIZZLE_ZERO;
-        viewInfo.components.g = VK_COMPONENT_SWIZZLE_ZERO;
-        viewInfo.components.b = VK_COMPONENT_SWIZZLE_ZERO;
-        viewInfo.components.a = VK_COMPONENT_SWIZZLE_ZERO;
         viewInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_STENCIL_BIT;
     }
 
     VkResult err = GR_VK_CALL(gpu->vkInterface(), CreateImageView(gpu->device(), &viewInfo,
                                                                   nullptr, &imageView));
     if (err) {
         return nullptr;
     }
 
     return new GrVkImageView(imageView);
 }
 
 void GrVkImageView::freeGPUData(const GrVkGpu* gpu) const {
     GR_VK_CALL(gpu->vkInterface(), DestroyImageView(gpu->device(), fImageView, nullptr));
 }