Set barriers and image layout changes between mipmap blits.

src/gpu/vk/GrVkTextureRenderTarget.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 "GrVkTextureRenderTarget.h"
 
 #include "GrRenderTargetPriv.h"
@@ skipping 11 matching lines @@
 GrVkTextureRenderTarget* GrVkTextureRenderTarget::Create(GrVkGpu* gpu,
                                                          ResourceType resourceType,
                                                          const GrSurfaceDesc& desc,
                                                          VkFormat format,
                                                          const GrVkImage::Resource* imageResource) {
     VkImage image = imageResource->fImage;
     // Create the texture ImageView
     uint32_t mipLevels = 1;
     //TODO: does a mipmapped textureRenderTarget make sense?
     //if (desc.fIsMipMapped) {
-    //    mipLevels = SkMipMap::ComputeLevelCount(this->width(), this->height());
+    //    mipLevels = SkMipMap::ComputeLevelCount(this->width(), this->height()) + 1;
     //}
     const GrVkImageView* imageView = GrVkImageView::Create(gpu, image, format,
                                                            GrVkImageView::kColor_Type, mipLevels);
     if (!imageView) {
         return nullptr;
     }
 
     VkFormat pixelFormat;
     GrPixelConfigToVkFormat(desc.fConfig, &pixelFormat);
 
@@ skipping 128 matching lines @@
     }
     GrVkTextureRenderTarget* trt = Create(gpu, kWrapped, desc, format, imageResource);
     if (trt) {
         trt->fCurrentLayout = info->fImageLayout;
     }
     // Create() will increment the refCount of the image resource if it succeeds
     imageResource->unref(gpu);
 
     return trt;
 }