Return gl::Error from VertexArray::syncState().

No functional change.
When we add vertex data format conversion to Vulkan we will need to be
able to return an error from VertexArray::syncState().

BUG=angleproject:2405

Change-Id: I4b537946ecbb6593280b6510c5cd8d8e3c65e8dd
Reviewed-on: https://chromium-review.googlesource.com/982897
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>
Reviewed-by: Luc Ferron <lucferron@chromium.org>
diff --git a/src/libANGLE/renderer/vulkan/VertexArrayVk.cpp b/src/libANGLE/renderer/vulkan/VertexArrayVk.cpp
index 5e9a779..bbc6895 100644
--- a/src/libANGLE/renderer/vulkan/VertexArrayVk.cpp
+++ b/src/libANGLE/renderer/vulkan/VertexArrayVk.cpp
@@ -93,10 +93,10 @@
     return gl::NoError();
 }
 
-void VertexArrayVk::syncState(const gl::Context *context,
-                              const gl::VertexArray::DirtyBits &dirtyBits,
-                              const gl::VertexArray::DirtyAttribBitsArray &attribBits,
-                              const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
+gl::Error VertexArrayVk::syncState(const gl::Context *context,
+                                   const gl::VertexArray::DirtyBits &dirtyBits,
+                                   const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                                   const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
 {
     ASSERT(dirtyBits.any());
 
@@ -159,6 +159,8 @@
             UNIMPLEMENTED();
         }
     }
+
+    return gl::NoError();
 }
 
 const gl::AttribArray<VkBuffer> &VertexArrayVk::getCurrentArrayBufferHandles() const