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/gl/VertexArrayGL.cpp b/src/libANGLE/renderer/gl/VertexArrayGL.cpp
index 7496733..329a2f4 100644
--- a/src/libANGLE/renderer/gl/VertexArrayGL.cpp
+++ b/src/libANGLE/renderer/gl/VertexArrayGL.cpp
@@ -701,10 +701,10 @@
     }
 }
 
-void VertexArrayGL::syncState(const gl::Context *context,
-                              const VertexArray::DirtyBits &dirtyBits,
-                              const gl::VertexArray::DirtyAttribBitsArray &attribBits,
-                              const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
+gl::Error VertexArrayGL::syncState(const gl::Context *context,
+                                   const VertexArray::DirtyBits &dirtyBits,
+                                   const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                                   const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
 {
     mStateManager->bindVertexArray(mVertexArrayID, getAppliedElementArrayBufferID());
 
@@ -734,6 +734,8 @@
             }
         }
     }
+
+    return gl::NoError();
 }
 
 void VertexArrayGL::applyNumViewsToDivisor(int numViews)