D3D: Return error from getVertexSpaceRequired.

This removes another use of the gl::ErrorOrResult pattern. Unblocks
error refactoring.

Bug: angleproject:2738
Change-Id: Ib611a3b68f8995469befd51797dfed34eaeee84e
Reviewed-on: https://chromium-review.googlesource.com/1151450
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
diff --git a/src/tests/perf_tests/IndexDataManagerTest.cpp b/src/tests/perf_tests/IndexDataManagerTest.cpp
index a85d212..d4d627e 100644
--- a/src/tests/perf_tests/IndexDataManagerTest.cpp
+++ b/src/tests/perf_tests/IndexDataManagerTest.cpp
@@ -55,12 +55,13 @@
     MOCK_METHOD0(createVertexBuffer, rx::VertexBuffer *());
     MOCK_CONST_METHOD1(getVertexConversionType, rx::VertexConversionType(gl::VertexFormatType));
     MOCK_CONST_METHOD1(getVertexComponentType, GLenum(gl::VertexFormatType));
-    MOCK_CONST_METHOD5(getVertexSpaceRequired,
-                       gl::ErrorOrResult<unsigned int>(const gl::Context *,
-                                                       const gl::VertexAttribute &,
-                                                       const gl::VertexBinding &,
-                                                       size_t,
-                                                       GLsizei));
+    MOCK_CONST_METHOD6(getVertexSpaceRequired,
+                       gl::Error(const gl::Context *,
+                                 const gl::VertexAttribute &,
+                                 const gl::VertexBinding &,
+                                 size_t,
+                                 GLsizei,
+                                 unsigned int *));
 
     // Dependency injection
     rx::IndexBuffer *createIndexBuffer() override