Add automatic generation of mipmaps to Vulkan

src/gpu/vk/GrVkSampler.h

Index: src/gpu/vk/GrVkSampler.h
diff --git a/src/gpu/vk/GrVkSampler.h b/src/gpu/vk/GrVkSampler.h
index ec97751cbbda75fb5d96d971304d830a9ad97054..2aa5017aad2e024bce2d9e34d67f5209a9005e82 100644
--- a/src/gpu/vk/GrVkSampler.h
+++ b/src/gpu/vk/GrVkSampler.h
@@ -19,22 +19,22 @@ class GrVkGpu;
 
 class GrVkSampler : public GrVkResource {
 public:
-    static GrVkSampler* Create(const GrVkGpu* gpu, const GrTextureParams&);
+    static GrVkSampler* Create(const GrVkGpu* gpu, const GrTextureParams&, uint32_t mipLevels);
 
     VkSampler sampler() const { return fSampler; }
 
     // Helpers for hashing GrVkSampler
-    static uint8_t GenerateKey(const GrTextureParams&);
+    static uint16_t GenerateKey(const GrTextureParams&, uint32_t mipLevels);
 
-    static const uint8_t& GetKey(const GrVkSampler& sampler) { return sampler.fKey; }
-    static uint32_t Hash(const uint8_t& key) { return key; }
+    static const uint16_t& GetKey(const GrVkSampler& sampler) { return sampler.fKey; }
+    static uint32_t Hash(const uint16_t& key) { return key; }
 private:
-    GrVkSampler(VkSampler sampler, uint8_t key) : INHERITED(), fSampler(sampler), fKey(key) {}
+    GrVkSampler(VkSampler sampler, uint16_t key) : INHERITED(), fSampler(sampler), fKey(key) {}
 
     void freeGPUData(const GrVkGpu* gpu) const override;
 
     VkSampler  fSampler;
-    uint8_t   fKey;
+    uint16_t   fKey;
 
     typedef GrVkResource INHERITED;
 };