Replace _countof with ArraySize

This macro only exists on MSVC

BUG=None

Change-Id: I23204d1307279840a7f85a005da9ed5c324e7dae
Reviewed-on: https://chromium-review.googlesource.com/309800
Tryjob-Request: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/tests/gl_tests/D3D11EmulatedIndexedBufferTest.cpp b/src/tests/gl_tests/D3D11EmulatedIndexedBufferTest.cpp
index dc7f43b..3660c19 100644
--- a/src/tests/gl_tests/D3D11EmulatedIndexedBufferTest.cpp
+++ b/src/tests/gl_tests/D3D11EmulatedIndexedBufferTest.cpp
@@ -43,7 +43,7 @@
 
         GLubyte indices[] = {0, 0, 3, 4, 2, 1, 1};
 
-        for (size_t i = 0; i < _countof(indices); i++)
+        for (size_t i = 0; i < ArraySize(indices); i++)
         {
             mExpectedExpandedData.push_back(testData[indices[i]]);
             mubyteIndices.push_back(indices[i]);