Consolidate GPU buffer implementations

src/gpu/vk/GrVkGpu.cpp

Index: src/gpu/vk/GrVkGpu.cpp
diff --git a/src/gpu/vk/GrVkGpu.cpp b/src/gpu/vk/GrVkGpu.cpp
index 96c74ddd5dc1df2217723b50877adb93baec072d..c0eb48a55dfcad616f9b108e79b68639cf8de74d 100644
--- a/src/gpu/vk/GrVkGpu.cpp
+++ b/src/gpu/vk/GrVkGpu.cpp
@@ -389,11 +389,11 @@ void GrVkGpu::submitCommandBuffer(SyncQueue sync) {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
-GrVertexBuffer* GrVkGpu::onCreateVertexBuffer(size_t size, bool dynamic) {
+GrBuffer* GrVkGpu::onCreateVertexBuffer(size_t size, bool dynamic) {
     return GrVkVertexBuffer::Create(this, size, dynamic);
 }
 
-GrIndexBuffer* GrVkGpu::onCreateIndexBuffer(size_t size, bool dynamic) {
+GrBuffer* GrVkGpu::onCreateIndexBuffer(size_t size, bool dynamic) {
     return GrVkIndexBuffer::Create(this, size, dynamic);
 }