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

src/gpu/vk/GrVkPipelineStateDataManager.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "GrVkPipelineStateDataManager.h"
 
 #include "GrVkGpu.h"
@@ skipping 235 matching lines @@
 };
 
 template<> struct set_uniform_matrix<4> {
     inline static void set(void* buffer, int uniformOffset, int count, const float matrices[]) {
         GR_STATIC_ASSERT(sizeof(float) == 4);
         buffer = static_cast<char*>(buffer) + uniformOffset;
         memcpy(buffer, matrices, count * 16 * sizeof(float));
     }
 };
 
-void GrVkPipelineStateDataManager::uploadUniformBuffers(const GrVkGpu* gpu,
+bool GrVkPipelineStateDataManager::uploadUniformBuffers(const GrVkGpu* gpu,
                                                         GrVkUniformBuffer* vertexBuffer,
                                                         GrVkUniformBuffer* fragmentBuffer) const {
+    bool updatedBuffer = false;
     if (vertexBuffer && fVertexUniformsDirty) {
         vertexBuffer->addMemoryBarrier(gpu,
                                        VK_ACCESS_UNIFORM_READ_BIT,
                                        VK_ACCESS_HOST_WRITE_BIT,
                                        VK_PIPELINE_STAGE_VERTEX_SHADER_BIT,
                                        VK_PIPELINE_STAGE_HOST_BIT,
                                        false);
-        SkAssertResult(vertexBuffer->updateData(gpu, fVertexUniformData.get(), fVertexUniformSize));
+        SkAssertResult(vertexBuffer->updateData(gpu, fVertexUniformData.get(), fVertexUniformSize,
+                                                &updatedBuffer));
         fVertexUniformsDirty = false;
     }
 
     if (fragmentBuffer && fFragmentUniformsDirty) {
         fragmentBuffer->addMemoryBarrier(gpu,
                                          VK_ACCESS_UNIFORM_READ_BIT,
                                          VK_ACCESS_HOST_WRITE_BIT,
                                          VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,
                                          VK_PIPELINE_STAGE_HOST_BIT,
                                          false);
         SkAssertResult(fragmentBuffer->updateData(gpu, fFragmentUniformData.get(),
-                                                  fFragmentUniformSize));
+                                                  fFragmentUniformSize, &updatedBuffer));
         fFragmentUniformsDirty = false;
     }
+    return updatedBuffer;
 }