Clean up ANGLE test extension functions.

None of these functions needed to be member functions. Also make the
naming more consistent.

Bug: angleproject:3393
Change-Id: I7aafe2269a48af703a87bd9a8cf4cfab9e177dd3
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1574673
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/tests/gl_tests/FramebufferMultiviewTest.cpp b/src/tests/gl_tests/FramebufferMultiviewTest.cpp
index ad7dc48..bffa7e5 100644
--- a/src/tests/gl_tests/FramebufferMultiviewTest.cpp
+++ b/src/tests/gl_tests/FramebufferMultiviewTest.cpp
@@ -740,7 +740,7 @@
 {
     ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());
 
-    ANGLE_SKIP_TEST_IF(!ensureExtensionEnabled("GL_OES_texture_storage_multisample_2d_array"));
+    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_OES_texture_storage_multisample_2d_array"));
 
     // We don't enable OVR_multiview2_multisample