Switch uniforms to be descriptor set 0 in Vulkan

src/gpu/vk/GrVkPipelineState.cpp

Index: src/gpu/vk/GrVkPipelineState.cpp
diff --git a/src/gpu/vk/GrVkPipelineState.cpp b/src/gpu/vk/GrVkPipelineState.cpp
index dacd66b0e7e90fffad5ea7f55259b13d481e28a0..90a27e35a76a4b3e1f28310f7ec72da90ceb0955 100644
--- a/src/gpu/vk/GrVkPipelineState.cpp
+++ b/src/gpu/vk/GrVkPipelineState.cpp
@@ -37,6 +37,8 @@ GrVkPipelineState::GrVkPipelineState(GrVkGpu* gpu,
                                      const GrGLSLFragProcs& fragmentProcessors)
     : fPipeline(pipeline)
     , fPipelineLayout(layout)
+    , fStartDS(SK_MaxS32)
+    , fDSCount(0)
     , fBuiltinUniformHandles(builtinUniformHandles)
     , fGeometryProcessor(geometryProcessor)
     , fXferProcessor(xferProcessor)
@@ -46,7 +48,8 @@ GrVkPipelineState::GrVkPipelineState(GrVkGpu* gpu,
     , fSamplerPoolManager(dsLayout[GrVkUniformHandler::kSamplerDescSet],
                           VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, numSamplers, gpu)
     , fUniformPoolManager(dsLayout[GrVkUniformHandler::kUniformBufferDescSet],
-                          VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 2, gpu) {
+                          VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
+                          (vertexUniformSize || fragmentUniformSize) ? 2 : 0, gpu) {
     fSamplers.setReserve(numSamplers);
     fTextureViews.setReserve(numSamplers);
     fTextures.setReserve(numSamplers);
@@ -55,8 +58,10 @@ GrVkPipelineState::GrVkPipelineState(GrVkGpu* gpu,
     fDescriptorSets[1] = VK_NULL_HANDLE;
 
     // Currently we are always binding a descriptor set for uniform buffers.
-    fStartDS = GrVkUniformHandler::kUniformBufferDescSet;
-    fDSCount = 1;
+    if (vertexUniformSize || fragmentUniformSize) {
+        fDSCount++;
+        fStartDS = GrVkUniformHandler::kUniformBufferDescSet;
+    }
     if (numSamplers) {
         fDSCount++;
         fStartDS = SkTMin(fStartDS, (int)GrVkUniformHandler::kSamplerDescSet);
@@ -189,13 +194,15 @@ void GrVkPipelineState::setData(GrVkGpu* gpu,
     if (fNumSamplers) {
         fSamplerPoolManager.getNewDescriptorSet(gpu,
                                              &fDescriptorSets[GrVkUniformHandler::kSamplerDescSet]);
+        this->writeSamplers(gpu, textureBindings);
     }
-    fUniformPoolManager.getNewDescriptorSet(gpu,
-                                       &fDescriptorSets[GrVkUniformHandler::kUniformBufferDescSet]);
 
-    this->writeUniformBuffers(gpu);
 
-    this->writeSamplers(gpu, textureBindings);
+    if (fVertexUniformBuffer.get() || fFragmentUniformBuffer.get()) {
+        fUniformPoolManager.getNewDescriptorSet(gpu,
+                                       &fDescriptorSets[GrVkUniformHandler::kUniformBufferDescSet]);
+        this->writeUniformBuffers(gpu);
+    }
 }
 
 void GrVkPipelineState::writeUniformBuffers(const GrVkGpu* gpu) {
@@ -218,7 +225,7 @@ void GrVkPipelineState::writeUniformBuffers(const GrVkGpu* gpu) {
 
         descriptorWrites[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
         descriptorWrites[0].pNext = nullptr;
-        descriptorWrites[0].dstSet = fDescriptorSets[1];
+        descriptorWrites[0].dstSet = fDescriptorSets[GrVkUniformHandler::kUniformBufferDescSet];
         descriptorWrites[0].dstBinding = GrVkUniformHandler::kVertexBinding;
         descriptorWrites[0].dstArrayElement = 0;
         descriptorWrites[0].descriptorCount = 1;
@@ -249,7 +256,7 @@ void GrVkPipelineState::writeUniformBuffers(const GrVkGpu* gpu) {
 
         descriptorWrites[1].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
         descriptorWrites[1].pNext = nullptr;
-        descriptorWrites[1].dstSet = fDescriptorSets[1];
+        descriptorWrites[1].dstSet = fDescriptorSets[GrVkUniformHandler::kUniformBufferDescSet];
         descriptorWrites[1].dstBinding = GrVkUniformHandler::kFragBinding;;
         descriptorWrites[1].dstArrayElement = 0;
         descriptorWrites[1].descriptorCount = 1;