Unify DescriptorPools for vulkan uniform descriptor sets

src/gpu/vk/GrVkDescriptorPool.h

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #ifndef GrVkDescriptorPool_DEFINED
 #define GrVkDescriptorPool_DEFINED
 
 #include "GrVkResource.h"
 
 #include "vk/GrVkDefines.h"
 
 class GrVkGpu;
 
 /**
  * We require that all descriptor sets are of a single descriptor type. We also use a pool to only
  * make one type of descriptor set. Thus a single VkDescriptorPool will only allocated space for
  * for one type of descriptor.
  */
 class GrVkDescriptorPool : public GrVkResource {
 public:
-    explicit GrVkDescriptorPool(const GrVkGpu* gpu, VkDescriptorType type, uint32_t count);
+    GrVkDescriptorPool(const GrVkGpu* gpu, VkDescriptorType type, uint32_t count);
 
     VkDescriptorPool descPool() const { return fDescPool; }
 
     void reset(const GrVkGpu* gpu);
 
     // Returns whether or not this descriptor pool could be used, assuming it gets fully reset and
     // not in use by another draw, to support the requested type and count.
     bool isCompatible(VkDescriptorType type, uint32_t count) const;
 
 private:
     void freeGPUData(const GrVkGpu* gpu) const override;
 
     VkDescriptorType     fType;
     uint32_t             fCount;
     VkDescriptorPool     fDescPool;
 
     typedef GrVkResource INHERITED;
 };
 
 #endif