Switch uniforms to be descriptor set 0 in Vulkan

src/gpu/vk/GrVkPipelineStateBuilder.cpp

Index: src/gpu/vk/GrVkPipelineStateBuilder.cpp
diff --git a/src/gpu/vk/GrVkPipelineStateBuilder.cpp b/src/gpu/vk/GrVkPipelineStateBuilder.cpp
index f9654c3af543c6fd653558e482bf7be714f6541b..3ea9e1b5d2a01ea0ed4c7aef8784403f4474d552 100644
--- a/src/gpu/vk/GrVkPipelineStateBuilder.cpp
+++ b/src/gpu/vk/GrVkPipelineStateBuilder.cpp
@@ -170,7 +170,7 @@ GrVkPipelineState* GrVkPipelineStateBuilder::finalize(GrPrimitiveType primitiveT
         UniformHandle uniHandle = fSamplerUniforms[i];
         GrVkUniformHandler::UniformInfo uniformInfo = fUniformHandler.getUniformInfo(uniHandle);
         SkASSERT(kSampler2D_GrSLType == uniformInfo.fVariable.getType());
-        SkASSERT(0 == uniformInfo.fSetNumber);
+        SkASSERT(GrVkUniformHandler::kSamplerDescSet == uniformInfo.fSetNumber);
         SkASSERT(uniformInfo.fBinding == i);
         dsSamplerBindings[i].binding = uniformInfo.fBinding;
         dsSamplerBindings[i].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
@@ -203,12 +203,12 @@ GrVkPipelineState* GrVkPipelineStateBuilder::finalize(GrPrimitiveType primitiveT
     memset(&dsUniBindings, 0, 2 * sizeof(VkDescriptorSetLayoutBinding));
     dsUniBindings[0].binding = GrVkUniformHandler::kVertexBinding;
     dsUniBindings[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
-    dsUniBindings[0].descriptorCount = fUniformHandler.hasVertexUniforms() ? 1 : 0;
+    dsUniBindings[0].descriptorCount = 1;

[egdaniel, 2016/04/06 20:22:48]

This is needed so that the layout for all our uniforms stays the same (and we
don't spend time invaliding unnecessary descriptor sets. We don't actually end
up making the extra uniform buffers, just saying the layout allows them. 

     dsUniBindings[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
     dsUniBindings[0].pImmutableSamplers = nullptr;
     dsUniBindings[1].binding = GrVkUniformHandler::kFragBinding;
     dsUniBindings[1].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
-    dsUniBindings[1].descriptorCount = fUniformHandler.hasFragmentUniforms() ? 1 : 0;
+    dsUniBindings[1].descriptorCount = 1;
     dsUniBindings[1].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
     dsUniBindings[1].pImmutableSamplers = nullptr;