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

src/gpu/vk/GrVkPipelineStateDataManager.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 GrVkPipelineStateDataManager_DEFINED
 #define GrVkPipelineStateDataManager_DEFINED
 
@@ skipping 28 matching lines @@
     void setMatrix2fv(UniformHandle, int arrayCount, const float matrices[]) const override;
     void setMatrix3fv(UniformHandle, int arrayCount, const float matrices[]) const override;
     void setMatrix4fv(UniformHandle, int arrayCount, const float matrices[]) const override;
 
     // for nvpr only
     void setPathFragmentInputTransform(VaryingHandle u, int components,
                                        const SkMatrix& matrix) const override {
         SkFAIL("Only supported in NVPR, which is not in vulkan");
     }
 
-    void uploadUniformBuffers(const GrVkGpu* gpu,
+    // Returns true if either the vertex or fragment buffer needed to generate a new underlying
+    // VkBuffer object in order upload data. If true is returned, this is a signal to the caller
+    // that they will need to update the descriptor set that is using these buffers.
+    bool uploadUniformBuffers(const GrVkGpu* gpu,
                               GrVkUniformBuffer* vertexBuffer,
                               GrVkUniformBuffer* fragmentBuffer) const;
 private:
     struct Uniform {
         uint32_t fBinding;
         uint32_t fOffset;
         SkDEBUGCODE(
             GrSLType    fType;
             int         fArrayCount;
             uint32_t    fSetNumber;
@@ skipping 10 matching lines @@
 
     SkTArray<Uniform, true> fUniforms;
 
     mutable SkAutoMalloc fVertexUniformData;
     mutable SkAutoMalloc fFragmentUniformData;
     mutable bool         fVertexUniformsDirty;
     mutable bool         fFragmentUniformsDirty;
 };
 
 #endif