Don't create new descriptor set for vulkan uniforms every draw

src/gpu/vk/GrVkBuffer.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrVkBuffer.h"
 #include "GrVkGpu.h"
 #include "GrVkMemory.h"
@@ skipping 145 matching lines @@
     VK_CALL(gpu, UnmapMemory(gpu->device(), alloc()));
 
     fMapPtr = nullptr;
 }
 
 bool GrVkBuffer::vkIsMapped() const {
     VALIDATE();
     return SkToBool(fMapPtr);
 }
 
-bool GrVkBuffer::vkUpdateData(const GrVkGpu* gpu, const void* src, size_t srcSizeInBytes) {
+bool GrVkBuffer::vkUpdateData(const GrVkGpu* gpu, const void* src, size_t srcSizeInBytes,
+                              bool* createdNewBuffer) {
     SkASSERT(!this->vkIsMapped());
     VALIDATE();
     if (srcSizeInBytes > fDesc.fSizeInBytes) {
         return false;
     }
 
     if (!fResource->unique()) {
         // in use by the command buffer, so we need to create a new one
         fResource->unref(gpu);
         fResource = Create(gpu, fDesc);
+        if (createdNewBuffer) {
+            *createdNewBuffer = true;
+        }
     }
 
     void* mapPtr;
     VkResult err = VK_CALL(gpu, MapMemory(gpu->device(), alloc(), 0, srcSizeInBytes, 0, &mapPtr));
 
     if (VK_SUCCESS != err) {
         return false;
     }
 
     memcpy(mapPtr, src, srcSizeInBytes);
 
     VK_CALL(gpu, UnmapMemory(gpu->device(), alloc()));
 
     return true;
 }
 
 void GrVkBuffer::validate() const {
     SkASSERT(!fResource || kVertex_Type == fDesc.fType || kIndex_Type == fDesc.fType
              || kCopyRead_Type == fDesc.fType || kCopyWrite_Type == fDesc.fType
              || kUniform_Type == fDesc.fType);
 }