Add automatic generation of mipmaps to Vulkan

src/gpu/vk/GrVkCommandBuffer.h

Index: src/gpu/vk/GrVkCommandBuffer.h
diff --git a/src/gpu/vk/GrVkCommandBuffer.h b/src/gpu/vk/GrVkCommandBuffer.h
index 1b27c5517dde0d5b41585525e56e10b852d615e3..b2f6ef013f73c8ebd89ffb5dcceb631be2c60e15 100644
--- a/src/gpu/vk/GrVkCommandBuffer.h
+++ b/src/gpu/vk/GrVkCommandBuffer.h
@@ -127,9 +127,9 @@ public:
                    const VkImageCopy* copyRegions);
 
     void blitImage(const GrVkGpu* gpu,
-                   GrVkImage* srcImage,
+                   const GrVkImage::Resource* srcImage,
                    VkImageLayout srcLayout,
-                   GrVkImage* dstImage,
+                   const GrVkImage::Resource* dstImage,
                    VkImageLayout dstLayout,
                    uint32_t blitRegionCount,
                    const VkImageBlit* blitRegions,