Perform Vulkan resets in a background thread

Bug: skia:
Change-Id: I90783dc9ac2fcae560cd54e6c8c6df11d7195ac0
Reviewed-on: https://skia-review.googlesource.com/c/168488
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/vk/GrVkDescriptorPool.cpp b/src/gpu/vk/GrVkDescriptorPool.cpp
index b89145a..ffb6626 100644
--- a/src/gpu/vk/GrVkDescriptorPool.cpp
+++ b/src/gpu/vk/GrVkDescriptorPool.cpp
@@ -44,7 +44,7 @@
     GR_VK_CALL_ERRCHECK(gpu->vkInterface(), ResetDescriptorPool(gpu->device(), fDescPool, 0));
 }
 
-void GrVkDescriptorPool::freeGPUData(const GrVkGpu* gpu) const {
+void GrVkDescriptorPool::freeGPUData(GrVkGpu* gpu) const {
     // Destroying the VkDescriptorPool will automatically free and delete any VkDescriptorSets
     // allocated from the pool.
     GR_VK_CALL(gpu->vkInterface(), DestroyDescriptorPool(gpu->device(), fDescPool, nullptr));