Default test window size to 16x16.

This fixes a crash on Linux whenever we try to create a test without
specifying a default width and height. Did not seem to have a problem
on Windows.

TEST=angle_end2end_tests (Windows/Linux)
BUG=angleproject:1123

Change-Id: I1afcea9e833208d8a67d363678b9736c2a222066
Reviewed-on: https://chromium-review.googlesource.com/298835
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/tests/test_utils/ANGLETest.cpp b/src/tests/test_utils/ANGLETest.cpp
index fe1a1e7..4df5349 100644
--- a/src/tests/test_utils/ANGLETest.cpp
+++ b/src/tests/test_utils/ANGLETest.cpp
@@ -4,8 +4,8 @@
 
 ANGLETest::ANGLETest()
     : mEGLWindow(nullptr),
-      mWidth(0),
-      mHeight(0)
+      mWidth(16),
+      mHeight(16)
 {
     mEGLWindow =
         new EGLWindow(GetParam().majorVersion, GetParam().minorVersion, GetParam().eglParameters);