Add automatic generation of mipmaps to Vulkan

src/gpu/vk/GrVkImageView.h

Index: src/gpu/vk/GrVkImageView.h
diff --git a/src/gpu/vk/GrVkImageView.h b/src/gpu/vk/GrVkImageView.h
index f70080852da21a6cac2101206336acc4f6ecc17f..4be0d199c66bdae24efed478887371d1c0ac6e97 100644
--- a/src/gpu/vk/GrVkImageView.h
+++ b/src/gpu/vk/GrVkImageView.h
@@ -21,7 +21,8 @@ public:
         kStencil_Type
     };
 
-    static const GrVkImageView* Create(GrVkGpu* gpu, VkImage image, VkFormat format, Type viewType);
+    static const GrVkImageView* Create(const GrVkGpu* gpu, VkImage image, VkFormat format, 
+                                       Type viewType, uint32_t miplevels);
 
     VkImageView imageView() const { return fImageView; }